Two-month-old male mice were exposed to whole-body hyperthermic treatment in a circulating water bath. After 1 h exposure to 41 degrees C, mice were kept at room temperature for 24, 48, 72, and 96 h before thymus examination. The total thymocyte number progressively decreased after 24 and 48 h, reached a minimum value at 72 h, and returned to almost normal value after 96 h. Similar changes occurred in the CD4+CD8+ cell subset. Conversely, the percentage of CD4-CD8- cells rose to a maximum at 48 h and then declined to normal value at 96 h. The percentage of CD4-CD8+ and CD4+CD8- cell subsets increased to a maximum at 48 h and then declined to normal value at 96 h. These variations in single positive cell subsets correlated well with similar changes in the thymocyte mitotic response to concanavalin A. The observed effects on thymocytes were heat dose dependent, and suggest that hyperthermia induces the development of the most primitive thymocytes and positively selects mature T cells with high mitotic responsiveness. It is proposed that heat shock proteins might be involved in the hyperthermia-induced alterations of thymocyte maturation and selection.

Animals↗

PubMed1992

Effect of synthetic thymic humoral factor (THF-gamma 2) on T cell activities in immunodeficient ageing mice.

Immunodeficient ageing (C57BL/10 x DBA/2)F1 mice were treated by a single injection of synthetic thymic hormones and 4 days later their thymus and spleen cells were assayed in vitro for T cell activities. A few nanograms of THF-gamma 2 were found to raise the frequency of mitogen-responsive T cells in thymus and spleen cell populations as well as the frequency of cytokine-producing splenic T cells, up to the levels observed in young mice. Moreover, injection of THF-gamma 2 was found to restore T cell growth factor (TCGF) production by mitogen-stimulated spleen cells. Also, the helper activity of spleen cells was enhanced by this treatment and increased with increasing the THF-gamma 2 dose over a wide range. Similarly, the effects of thymopentin and thymosin-alpha 1 on T helper cell activity increased with increasing the injected dose, but the efficiencies of THF-gamma 2 and thymopentin were, respectively, 400-fold and eight-fold greater than that of thymosin-alpha 1.

Aging↗

PubMed1991

Radiation protection and restoration by the synthetic 163-171 nonapeptide of human interleukin 1 beta.

We have previously reported that the synthetic nonapeptide VQGEESNDK, position 163-171 of human interleukin 1 (IL-1 beta), when injected in immunodepressed mice, shows immunorestorative activity similar to that of the whole protein, but with no IL-1-like inflammatory effects [Frasca et al., J. Immunol. 141, 2651-2655 (1988)]. In the present study we have compared the protective and restorative activities of the nonapeptide and human recombinant (hur) IL-1 beta on the survival of lethally irradiated mice. When mice were given a single injection of different doses of the nonapeptide or hurIL-1 beta 20 h before total-body irradiation, both molecules increased the percentage survival of mice exposed to 750 or 850 cGy, but not to 950 cGy. The nonapeptide, however, is less effective than hurIL-1 beta and displays a different dose-response relationship, suggesting that the two molecules act through different radioprotective pathways. When mice were injected with the nonapeptide or hurIL-1 beta immediately after exposure to 850 cGy, the percentage survival was also increased but restoration was lower than protection in both cases. The nonapeptide was also less effective than hurIL-1 beta in restoration, but the two molecules displayed a comparable dose-response relationship as if they shared similar mechanisms. These findings indicate that the 163-171 nonapeptide is able to protect from lethal radiation injury and to restore viability. The nonapeptide appears less effective than hurIL-1 beta but does not exhibit the IL-1-like side effects of the whole molecule.

Adjuvants, Immunologic↗

PubMed1990

Genetics of chemical carcinogenesis. 1. Bidirectional selective breeding of susceptible and resistant lines of mice to two-stage skin carcinogenesis.

Six generations of a bidirectional selective breeding model for producing lines of mice susceptible (Car-S) and resistant (Car-R) to two-stage skin carcinogenesis are described. Initiation was with 9,10-dimethyl-1,2-benzanthracene (DMBA single application), and promotion with 12-O-tetradecanoyl-phorbol-13-acetate (TPA twice weekly). The selective breeding was initiated with a highly genetically polymorph foundation population, produced by the intercrossing of eight inbred mouse strains. The Car-S line was produced by assortative mating of the mice presenting the largest number of tumors induced by low DMBA and TPA doses, the Car-R line by mating tumorless mice or mice showing the smallest number of tumors induced by large DMBA and TPA doses. The character investigated was expressed as per cent tumor incidence and as tumor multiplicity per mouse. The mean heritability of the susceptibility character for the two first generations was 0.84 for tumor incidence and 1.3 for tumor multiplicity; these values decreased to 0.53 and 0.44 respectively for the two consecutive generations. The heritability of the resistance character maintained a constant value of 0.29 +/- 0.04 for tumor incidence, and 0.53 +/- 0.08 for tumor multiplicity. The progressive response to selection indicates that the characters investigated are subject to polygenic regulation, even though some genes may have a major effect on the susceptibility character. The interline separation in F5, challenged with the same initiation and promotion schedule, is very large. In the Car-S line, tumor incidence was 82.5% and tumor multiplicity 4.9/mouse on promotion day 49, whereas the corresponding values for the Car-R line were 4.5% and 0.1/mouse on promotion day 81.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1990

[Multiparameter analysis of the ergometric test. Significance of the failure of systolic blood pressure to decrease during recovery phase as an index of coronary disease].

Ergometric tests were performed in 27 patients who had previously undergone coronarography following instrumental findings and/or symptoms which seemed highly indicative of ischemic cardiopathy. The aim of the study was to assess the diagnostic importance of the failure of systolic blood pressure to decrease during the third minute of the recovery phase of the test as an index of coronary disease. In particular, as reported by other studies, the ratio between systolic blood pressure at the third minute of recovery and maximum systolic blood pressure during the test was also assessed values above 0.7 were considered pathological. Sixteen out the 27 patients examined showed lesions which were hemodynamically significant, whereas 11 patients were free of lesions and 9 had previous myocardial necrosis. The level of the above ratio in subjects without significant coronary lesions was 0.66 +/- 0.05, whereas it was 0.85 +/- 0.04 (p less than 0.01) in patients with coronary disease. Sensitivity, specificity, and positive and negative prognostic values were respectively 91.6%, 62%, 64.7% and 90.9%. In patients with lesions to the three main arteries both the sensitivity and the specificity were 100%. In the same patients, the ST criteria were 85.7%, 50%, 81.8% and 74.3%.

Blood Pressure↗

PubMed1990

[Evaluation of acute cardiotoxicity from the combination cyclophosphamide-mitoxantrone-5-fluorouracil (CMF) with Holter ECG].

By making use of a twenty-four hour Holter monitoring, it as been possible to compute the acute cardiotoxicity of the cyclophosphamide + mitoxantrone + 5-fluorouracil (CNF) association in twenty oncologic patients (pts) each of whom being immune from organic cardiopathy emerging clinically and at their first cycle of chemotherapy. The following parameters have been computed: meaningful changes in the heart frequency; premature atrial and ventricular depolarizations, both as a first appearance and as a clear growth in the number; the ST dislocation entity; malignant ventricular arrhythmias. The administration of CNF at the doses of: 600 mg/m2 of cyclophosphamide, 12 mg/m2 of mitoxantrone and 600 mg/m2 of 5-fluorouracil , has caused a meaningful increase in the heart frequency on 6 pts (30%), an increase of premature atrial depolarization on 4 pts (20%) with an appearance ex novo on 2 pts (10%), an increase of premature ventricular depolarization, without any passing to superior Lown classes, on 2 pts (10%) with an appearance ex novo on 3 pts (15%). Although the results in the study point out a frequency percentage of simple hyperkinetic arrhythmias equal to the 55%, the lack of more serious hyperkinetic arrhythmias and of intense disorders of ventricular repolarization testified to a synergic effect as a determining factor on the acute cardiotoxicity of the previously discussed association, in our opinion.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1990

[3 cases of gingival hyperplasia during nifedipine therapy].

The authors report the cases of three male patients, aged 36, 54 and 52 years, who developed gingival hypertrophy during treatment with nifedipine at a dose of 40 mg/daily. Hypertrophy was the same as that observed in patients treated with anti-convulsive or cytostatic drugs, and may probably be due to interference with calcium ions and local factors. Full recovery was achieved by suspending nifedipine treatment in all patients.

Adult↗

PubMed1989

Competition for antigen presentation in living cells involves exchange of peptides bound by class II MHC molecules.

T cells recognize foreign proteins as peptides bound to self molecules encoded by the major histocompatibility complex (MHC). The kinetics of interaction between purified class II MHC molecules and peptides is unusual, in that the rate of association is very slow, but once formed, the complexes are extremely stable. This raises the question of how the antigen-presenting cell provides a sufficient number of free MHC binding sites to ensure T cell immunity. We present results suggesting that an exchange of peptide in MHC binding sites may take place under physiological conditions.

Ammonium Chloride↗

PubMed1989

Structural requirements for the interaction between peptide antigens and I-Ed molecules.

We have analyzed the structural characteristics of the interaction between I-Ed molecules and their peptide ligands. It was found that unrelated good I-Ed binders share structurally similar "core" regions that were experimentally demonstrated to be crucial for binding to I-Ed molecules. Single amino acid substitution analogues of one good I-Ed binder, hen egg lysozyme 107-116, were analyzed for their capacity to bind to I-Ed molecules and to activate two different I-Ed-restricted T cell hybridomas. The results illustrate the great permissiveness of I-Ed-peptide interaction and the great specificity of T cell recognition. It was concluded from these analyses that basic residues on the peptide molecule play a crucial role in binding to I-Ed. This contrasts with the structural requirements for binding to the other Iad isotype, I-Ad, the crucial hydrophobic residues. Thus, different class II molecules of the same MHC haplotype may have rather distinct peptide binding specificities, thereby expanding the repertoire of possible immunogenic peptides presented for T cell recognition.

Amino Acid Sequence↗

PubMed1989

Inheritance of immune responsiveness, life span, and disease incidence in interline crosses of mice selected for high or low multispecific antibody production.

High (H) and low (L) antibody responder lines of mice separated by selective breeding present a maximal interline difference in antibody (Ab) response to Ag of different specificities (general genetic regulation). The analysis of SRBC agglutinin response in H line, L line, F1 hybrids, F2, and backcross segregants demonstrates that Ab responsiveness is a polygenic trait regulated by the additive interaction of 5 to 7 independent loci, with an incomplete dominance (44% +/- 7%) of the high response character, and a 30% +/- 10% impact of the environmental factors. The life span of H, L, F1, F2, and backcross populations is correlated positively with 2-ME-resistant agglutinin response (r = 0.97, p less than 0.001) and negatively with 2-ME-sensitive agglutinin response (r = 0.95, p = 0.01) (interpopulation correlation). Similar correlations are also observed in individuals of the various populations, especially in F1 x L backcross, in which the largest phenotypic variance is found. The positive correlation between Ab responsiveness and life span was confirmed by ELISA titration for distinct IgG isotypes (intrapopulation correlation). Malignant lymphomas and chronic nephritis were the two most common diseases observed. The age-adjusted incidence of such diseases, which is largely affected by environmental factors, accounts for the longer life span of H, as compared with L, mouse populations. The longevity of the 30% or less survivors, chiefly determined by the rate of physiologic aging, is a polygenic character regulated by the cumulative interaction of 3 to 7 independent loci, with a complete dominance of the long life trait and an impact of the environmental factors of about 60%. Thus we have grounds for regarding general Ab responsiveness and life span as polygenic traits regulated by a small number of identical or closely linked gene loci, and immune responsiveness as a defense mechanism against neoplastic and inflammatory diseases.

Aging↗

PubMed1989

Cholinergic agonists selectively induce proliferative responses in the mature subpopulation of murine thymocytes.

The incubation of murine thymocytes for 24 hr in the presence of cholinergic agonists induces selective proliferation of PNA- cells as measured by thymidine incorporation. The response of PNA- cells is mediated by the activation of nicotinic receptors. This conclusion is suggested by the inability of the muscarinic agonist, oxotremorine, to induce cell proliferation and by the inhibition exerted by the nicotinic antagonist, d-tubocurarine. The presence of cholinergic axons in the murine thymus adds biological interest to the selective expression of functional cholinergic receptors on mature thymocytes.

Animals↗

PubMed1989

Age-related changes within a suppressor T cell circuit.

The effects of aging on cellular and molecular components of the 4-hydroxy-3-nitrophenyl acetyl-specific suppressor T (Ts) cell circuit were analyzed in vitro using inducer (Ts1), transducer (Ts2), and effector (Ts3) cells and activating factors (TsF1 and TsF2) derived from young or old mice. The activation of Ts2 cells by TsF1 and of Ts3 cells by TsF2 was found age-restricted, suggesting a loss of Ts2 and Ts3 cell subsets in old mice. However, the activation of Ts3 cells by small amounts of TsF2 is more efficient when both are derived from old rather than from young mice while the same level of maximum suppression is attained. Higher affinity of the interactions involved in Ts cell activation may compensate for loss of Ts cell subsets in old mice. No age restriction was found for antigen presentation to Ts1 cells and for the interaction between Ts3 cells and target B cells. Thus, the effects of aging on immunosuppression result from changes within the Ts cell circuit.

Aging↗

PubMed1989

An Apple IIE microcomputer program for multiple non-independent comparisons by the Scheffe's test.

When more than two groups of observations from the same set of experimental data are compared and pairwise tested for equality of their means, appropriate statistical treatment of the data is required. The overall variation in the set of data must be considered, and also the statistical non-independence of each pairwise comparison must be taken into account. We describe a simple Apple IIE microcomputer program that applies the Scheffe's test for multiple comparisons. A numerical example and a sample output of this program are also included. The listing of the program is reported in the Appendix.

Analysis of Variance↗