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Biomedical subjects

M Ennis

Publications and source records attributed to M Ennis.

191 records · Page 11Linked to original sources

The effect of alkaline earth cations on the release of histamine from rat peritoneal mast cells treated with compound 48/80 and peptide 401.

1 Extracellular calcium ions have a dual effect on the release of histamine from rat peritoneal mast cells treated with compound 48/80 and peptide 401. The release is either potentiated or inhibited according to the relative concentrations of ion and inducer.2 Strontium similarly potentiates the release produced by optimal concentrations of inducer but higher concentrations are required than in the case of calcium. Strontium is markedly less inhibitory than calcium.3 Mast cells may be depleted of intracellular calcium by incubation for short periods with the chelating agent, ethylenediamine tetraacetic acid (EDTA). They thereby become unresponsive to compound 48/80 and peptide 401 unless calcium is reintroduced into the incubation medium. Strontium and barium, but not magnesium, will substitute for calcium in this system. Barium additionally produces a marked release of histamine even in the absence of inducer. Pretreatment with the ionophore A23187 similarly inhibits the subsequent response to peptide 401 in divalent cation-free medium. This inhibition is reversed on the reintroduction of calcium.4 Compound 48/80 and peptide 401 release histamine from mast cells incubated in isotonic sucrose in the complete absence of added metal ions. However, the corrected release under these conditions is potentiated by both mono and divalent cations.5 On the basis of these results, the possible mechanism of action of the basic releasing agents and their usefulness as models for studying histamine secretion is discussed.

Animals↗

Effect of cyclic AMP on histamine release induced by compound 48/80.

Bu2 cAMP(N6, O2'-dibutyryl adenosine-3',5'-cyclic monophosphate) inhibited the response of rat peritoneal mast cells to compound 48/80 in the presence of calcium ions. In the absence of calcium, the nucleotide partially prevented the desensitization induced by chelating agents. The response of cells, allowed to accumulate Bu2 cAMP in the presence of calcium (to avoid depletion of intracellular stores of the ion) and then challenged in the absence of extracellular calcium, was also inhibited. These results are discussed in terms of the postulated effects of Bu2 cAMP on the calcium-gatubg mechanism operative in histamine secretion.

Animals↗

On the mechanism of immunosympathectomy.

The effects in vivo and in vitro of the antiserum to mouse nerve growth factor (NGF) are independent of the presence of complement. These results are consistent with the view that the antiserum acts by neutralizing endogenous NGF.

Animals↗

The mitogenic response of cryopreserved human lymphocytes in a microculture system.

Fresh blood lymphocytes from nine health donors have been compared with samples from the same donors, recovered after period of 2 to 21 months storage in liquid nitrogen, for the capacity to respond to a range of mitogens in vitro. A microculture assay was used, requireing aliquots of only 25,000 cells. The mean levels of 14C-thymidine uptake for fresh and frozen samples were closely comparable when the cells had been stimulated by PHA, Pokeweed or mitomycin-C-treated allogeneic lymphoblastoid cells. Lymphocytes from six East African donors, frozen by a very simple technique, were recovered after 3 or more years storage in liquid nitrogen. Five of the samples were in good condition as judged by cell viability and the capacity to form spontaneous 'E' rosettes with sheep erythrocytes. These five samples also responded extremely well to PHA, PWM and mitomycin-C-treated allogeneic lymphoblastoid cells using the microculture assay. This study extends the range of applications of cell banks in which small aliquots of blood lymphocytes are stored in liquid nitrogen for periods of several years.

Adult↗

Perioperative uses of histamine antagonists.

Histamine release and adverse pseudoallergic/allergic reactions during the perioperative period occur frequently. The incidence of such reactions is 20%-30% for all grades of severity, 1%-5% for systemic reactions, and 0.1%-0.5% for life-threatening reactions. They can be elicited by all commonly used anesthetic agents and by surgical interventions. Both the incidence and severity can be reduced by the use of combined prophylaxis with H1- + H2-receptor antagonists. The authors recommend that this prophylaxis be given to the following groups of patients: those with a history of adverse reactions or history of allergy, patients undergoing surgery with a high risk of histamine release, elderly patients, and those with poor physical status due to underlying systemic diseases. These indications have been developed by heuristic medical decision-making, including a decision tree.

Histamine H1 Antagonists↗

The relationship of cortisol to practice-related gains in intelligence among older persons.

Based on data collected from two separate samples of older adults, the present study explored the role of cortisol in mediating practice-related gains in fluid intelligence (Gf) among older adults. Analyses across samples involved treatment group participants who received stress inoculation training in order to reduce anxiety concerning intellectual performance; waiting list control group participants did not receive training until the experiment(s) were completed. Practice effects were examined for both groups. In Study 1, the sample consisted of a heterogeneous (re: concerns about intellectual performance) group of older adults, and Study 2 participants were older adults who self-reported as being at least moderately anxious or concerned about intellectual performance declines. The two samples differed on health (p < .01), with Study 2 participants being healthier (as determined via self-report). Results indicated that practice, but not training, effects were evident for measures of crystallized ability (Gc) and Gf across both studies. The data also suggested that cortisol mediation was different for the two samples in that it was negatively correlated with Gf in the first sample, and, though not significant, positively correlated with Gf in the second. The same directional relationships were evident for the measure of Gc. Comparisons between studies regarding correlations between cortisol and practice-related gains in performance were significant for Gf (p < .01) and approached significance for Gc (p < .07). These data seem to suggest that for some older persons, higher levels of cortisol interfere with the effects of practice on Gf performance, while for others, higher cortisol facilitates such gains in performance.

Aged↗

Comparisons of urinary versus serum cortisol in older persons.

The present analysis compared urine- versus serum-based amounts of the stress hormone cortisol in two older adult samples, given that urine as a sample medium is a less expensive and less invasive method of determining cortisol amounts relative to serum. Seventy-three older adults provided urine samples as part of an ongoing study to assess levels of cortisol as a function of intellectual efficacy/performance; these data were compared to serum cortisol levels obtained from 96 older adults in a separate study examining health beliefs and cortisol levels. Analyses indicated that the cortisol levels did not differ across samples, i.e., cortisol amounts measured in serum or urine yielded similar, typical (within normal ranges) results. The data, though preliminary, indicate that urine may provide an alternative to serum when assessing cortisol in older persons.

Adult↗

Anxiety is a good indicator for somatic symptom reduction through behavioral medicine intervention in a mind/body medicine clinic.

BACKGROUND: This study examined the effect of anxiety on symptom reduction through a behavioral medicine intervention in a Mind/Body Medicine Clinic. METHOD: Participants were 1,312 outpatients attending a 10-week behavioral medicine intervention which included training in the relaxation response, cognitive restructuring, exercise and nutrition. All of the patients had physical symptoms and were referred to the clinic by their physician. The Medical Symptom Checklist (12 major symptoms), Symptom Checklist 90 Revised (SCL-90R), Stress Perception Scale and the Health-Promoting Lifestyle Profile were administered before and after the program. RESULTS: Of the sample, 1,012 patients completed the program, and 911 completed the posttreatment assessment. Self-reported frequency of medical symptoms, degree of discomfort and interference with daily activities were significantly reduced as a result of the program. Anxiety and other psychological distress as measured by the SCL-90R and stress perception scales also showed significant reductions. Furthermore, health-promoting lifestyle functioning significantly improved. High levels of pretreatment anxiety predicted a decrease in the total number of medical symptoms endorsed. CONCLUSIONS: Behavioral medicine interventions are effective in reducing medical symptoms coinciding with improvement in anxiety. High anxiety at program entry may predict better outcome.

Adult↗

Prognostic awareness and the terminally ill.

The authors rated patients who were in advanced stages of cancer and in their final few weeks of life on their level of awareness of their medical prognosis (N = 200, mean age = 71.0 years). The authors measured prognostic awareness with a semistructured interview, dividing patients into those acknowledging No Awareness, Partial Awareness, and Complete Awareness. The authors also administered a semistructured interview for depressive disorders, along with an assessment of various demographic and social support measures. Nineteen patients (9.5%) denied awareness of both their terminal prognosis and foreshortened life expectancy. Thirty-four patients (17%) were placed in the partial awareness category, with the remaining 147 patients (73.5%) reporting complete awareness. Depression was nearly three times greater among patients who did not acknowledge their prognosis, as compared with those who demonstrated partial or complete acknowledgment (chi2 = 7.094), P = 0.029). In addition to depression, male patients, older patients, and those having "intense social contact" were associated with lower ratings of prognostic awareness. Dying patients differ in respect to their capacity to acknowledge their prognosis. Prognostic disavowal is most likely to arise in patients with underlying psychological distress and emotional turmoil.

Adaptation, Psychological↗