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D Cassell

Publications and source records attributed to D Cassell.

10 recordsLinked to original sources
PubMed1995

Serial changes in left ventricular function after coronary artery bypass: implications in viability assessment.

Improvement in left ventricular (LV) performance after coronary artery bypass surgery remains the gold standard in myocardial viability assessment. The time-related changes, however, are not well known. This study examined the LV ejection fraction (EF) by gated blood pool imaging early (6 +/- 4 days) and late (62 +/- 24 days) after surgery in patients with normal preoperative EF (group 1, n = 12) and those with LV dysfunction (group 2, n = 15). There were no changes in the clinical status between the early and late studies, and all patients had normal sinus rhythm. Group 1 had no significant change in EF (preoperatively 62%, early postoperatively 64%, late postoperatively 63%; p = NS). In group 2, EF was 26% +/- 8% preoperatively; 30% +/- 10% early postoperatively; and 34% +/- 8% late postoperatively (p < 0.05). Postoperatively there was > or = 5% improvement in EF in 4 patients early and 11 patients late (p < 0.05). Patients who showed early improvement continued to do so in the late study but, additionally, 7 patients showed improvement only in the late study. Thus the timing of EF measurement after surgery is important in patients with LV dysfunction but not in patients with normal LV function. Early assessment may underestimate the prevalence and degree of recovery.

Aged↗
PubMed1993

Effects of three colors in an office interior on mood and performance.

This study examined the effects of three hues on subjects' performance and mood while in an office work environment for 1 hour. Pretest/posttest measurements were completed. Work performance was measured using words typed, typing errors, and a ratio of errors to words typed. Anxiety, depression, and arousal were measured by the Eight State Questionnaire of Curran and Cattell. A total of 45 women, ages 18 to 24 years, were tested individually in a single office space: 15 when the office walls were painted red/warm, 15 when walls were blue-green/cool, and 15 when walls were white/neutral. Analysis of covariance of posttest measurements with the pretest as a covariate showed no significant differences among the three groups on performance or scores on anxiety, depression, and arousal. If color of the environment has an effect on work performance or mood, either the effect was too small to be detected with samples of 15 subjects or longer participation than one hour was required.

Adult↗
PubMed1991

Two roles for CD4 cells in the control of the generation of cytotoxic T lymphocytes.

The generation of CTL against Qa-1 Ag in C57BL/6 (B6) (Qa-1b) and B6.Tlaa (Qa-1a) congenic strains requires in vivo priming with the Qa-1 alloantigen together with a helper Ag, such as H-Y. The primed precursors obtained from these female mice generate Qa-1-specific CTL activity upon culture in vitro. Although the presence of the H-Y helper Ag is not required for the in vitro sensitization, no response occurs in the absence of CD4 cells. Addition of unprimed B6.Tlaa CD4 cells from Qa-1 incompatible radiation bone marrow chimeras (B6.Tlaa----B6), that are presumably tolerant to Qa-1b, provide helper activity for Qa-1b-specific CTL. This indicates that although CD4 cells are obligatory for the Qa-1 response, they need not be specific for alloantigens on the APC to generate helper activity in in vitro cultures. Addition of unirradiated B6 CD8-depleted spleen cells to CD4-depleted B6.Tlaa anti-B6 cultures in the presence of either B6.Tlaa CD4 cells or rIL-2 prevents the generation of Qa-1 specific CTL. This inhibition is not due to an anti-idiotypic Ts cell since B6.Tlaa----B6 chimeric cells do not suppress an anti-Qa-1b response. Rather, this finding is consistent with that of a veto cell mechanism. To determine whether CD4 cells themselves exhibit veto activity, highly purified CD4 populations were tested for their ability to inhibit the generation of Qa-1-specific CTL. CD4 cells precultured for 2 to 3 days with Con A and rIL-2 specifically inhibit CTL activity whereas resting cells do not, similar to that noted for CD8 veto cells. The relative efficiency of activated CD4 cells is greater than that of resting NK cells but is less than that of activated CD8 or NK cells. Thus, CD4 cells not only provide helper activity for CTL precursors, but also act as veto cells to prevent the generation of CTL activity.

Animals↗
PubMed1988

Linked recognition of helper and cytotoxic antigenic determinants for the generation of cytotoxic T lymphocytes.

These studies present a model for T-T collaboration for the generation of cytotoxic T lymphocytes. The in vitro CTL response against Qa-1 alloantigens in B6 Qa-1 congenic mice requires that animals are first primed in vivo with Qa-1 together with a second (helper) antigen. Both the antigen recognized by CTL (Qa-1) and Th (H-Y) must be presented on the same APC for successful priming. This findings is consistent with a linked recognition model whereby both molecules are presented on the same APC in order to accomplish close proximity between the two T cells. To further test this model, we demonstrated that in the absence of the helper antigen, H-Y, mice could be successfully primed against Qa-1 if coinoculated with a product of a Th, IL-2. We further showed that mice treated with anti-L3T4 antibodies could not be primed to Qa-1 even though the cells used for immunization expressed the H-Y helper antigen. Taken together, these results lend further support to a model of linked recognition between Th and CTL.P where close proximity allows for the lymphokine IL-2 to bind to its receptor on the CTL allowing for the successful induction of CTL.P.

Animals↗
PubMed1977

The stress factor.

Explore the source record for details and available documents.

Cardiovascular Diseases↗
PubMedDate not supplied

Assessment of myocardial viability by dynamic tomographic iodine 123 iodophenylpentadecanoic acid imaging: comparison with rest-redistribution thallium 201 imaging.

BACKGROUND: This study examined the ability of dynamic 123I-labeled iodophenylpentadecanoic acid (IPPA) imaging to detect myocardial viability in patients with left ventricular (LV) dysfunction caused by coronary artery disease. METHODS AND RESULTS: Serial 180-degree single-photon emission computed tomographic (SPECT) images (five sets, 8 minutes each) were obtained starting 4 minutes after injection of 2 to 6 mCi 123I at rest in 21 patients with LV dysfunction (ejection fraction [EF] 34% +/- 11%). The segmental uptake was compared with that of rest-redistribution 201Tl images (20 segments/study). The number of perfusion defects (reversible and fixed) was similar by IPPA and thallium (11 +/- 5 vs 10 +/- 5 segments/patient; difference not significant). There was agreement between IPPA and thallium for presence or absence (kappa = 0.78 +/- 0.03) and nature (reversible, mild fixed, or severe fixed) of perfusion defects (kappa = 0.54 +/- 0.04). However, there were more reversible IPPA defects than reversible thallium defects (7 +/- 4 vs 3 +/- 4 segments/patient; p = 0.001). In 14 patients the EF (by gated pool imaging) improved after coronary revascularization from 33% +/- 11% to 39% +/- 12% (p = 0.002). The number of reversible IPPA defects was greater in the seven patients who had improvement in EF than in the patients without such improvement (10 +/- 4 vs 5 +/- 4 segments/patient; p = 0.075). CONCLUSIONS: 123I-labeled IPPA SPECT imaging is a promising new technique for assessment of viability. Reversible defects predict recovery of LV dysfunction after coronary revascularization.

Adult↗