thymic-factor--circulating and Body-Weight

The present study tested the hypothesis that inadequate Zn intake might be responsible for failure to thrive and impaired catch-up growth in young rural Gambian children, and that Zn supplements might be beneficial. Gambian children might be deprived of Zn because of its poor availability from their predominantly plant-based diet. Rural Gambian children (110; fifty boys, sixty girls) aged between 0.57 and 2.30 years were divided into two matched groups, one to receive 70 mg Zn twice weekly for 1.25 years, and the other a placebo. Growth and mid-upper-arm circumference were measured at weekly intervals throughout the study and illnesses were monitored. Capillary blood and urine samples were collected at 0, 2 and 8 weeks. Body weights and arm circumferences showed a linear increase, plus a seasonal effect (rainy season faltering). For body weight there was no significant overall effect of the supplement. For arm circumference, a very small (2%) but significant (P < 0.01) difference favoured the supplemented group. Plasma thymulin was much lower at the first clinic than at the second and third clinics, and in vitro Zn stimulation was greater at the first clinic. There was, however, no effect of Zn in vivo. Likewise, Zn did not significantly benefit T-cell numbers or ratios, secretory IgA in urine, circulating hormone levels or biochemical indices of Zn status. One index of intestinal permeability, i.e. lactulose: creatinine, was improved (P < 0.02) by the supplement, but the lactulose: mannitol value was not; this requires further investigation. Dietary Zn deficiency is, thus, unlikely to be of major overall importance for rural Gambian children's ability to thrive, and blanket Zn supplementation is not justified. There may, however, be vulnerable sub-groups who would benefit from Zn supplements.

Topics: Anthropometry; Arm; Body Weight; CD4-CD8 Ratio; Child, Preschool; Complement C3; Double-Blind Method; Female; Food, Fortified; Gambia; Hemoglobins; Humans; Immunoglobulin A, Secretory; Infant; Male; Rural Population; Thymic Factor, Circulating; Time Factors; Zinc

It is found that 3 months after removal of thyroid gland in rats, a suppression of thymic endocrine function, loss of weight and cellularity occurs. These changes are mainly caused by a weakening of index of proliferative activity. In animals that postoperatively received substitutive thyroxin hormonotherapy and courses of thymulin these disorders don't occur or they are not expressed significantly.

Topics: Animals; Apoptosis; Body Weight; Cell Proliferation; Hormone Replacement Therapy; Male; Organ Size; Rats; Thymus Gland; Thymus Hormones; Thyroidectomy; Thyroxine

The effect of thymalin on peroxidation of lipids in thyroidectomized rats that received thyroxin at a dose 2 mg/ kg was examined. It was found that 3 months after operation a decrease in body weight (over 2 times), weight of spleen and amount of cells in it took place. An increase of TB-activated products in livers and spleens of thyroidectomized rats 3 month later was not essential. Indices of enzyme activity of antioxidant system in liver were within normal ranges while indices of activity of catalase and superoxidedysmuthase in spleen increased by 4,3 and 1,3 times, respectively. Simultaneous administration of thyroxin and thymalin promotes more effective normalization of POL peroxidation, inhibits development of pathologic changes in organism after removal of thyroid gland.

Topics: Animals; Antioxidants; Body Weight; Catalase; Drug Therapy, Combination; Hormone Replacement Therapy; Lipid Peroxides; Liver; Male; Organ Size; Rats; Rats, Wistar; Spleen; Superoxide Dismutase; Thymus Hormones; Thyroidectomy; Thyroxine

Since the potential effects of early exposure to lead on thymic functions have not been fully characterized, in this study we evaluated the capacity of lead to alter thymic function in juvenile chickens following embryonic exposure.. Cornell K strain White Leghorn chicken eggs were administered lead acetate (400 microg/egg) or sodium acetate (control) on embryonic development (E12) with and without thymulin supplementation. Ex vivo production of interferon-gamma (IFN-gamma)-like cytokine by thymocytes and a delayed-type hypersensitivity (DTH) reaction were measured in the juvenile. Additionally, the effects of in vitro exposure to lead on both thymocytes and thymic stromal cells (TSCs) were evaluated.. Following E12 exposure to lead, ex vivo production of IFN-gamma-like cytokine by juvenile-derived thymocytes decreased significantly compared to the control. The same effect was observed when thymocytes were directly exposed to lead in vitro and stimulated with thymic stromal supernatant. In contrast, when TSCs were exposed to lead in vitro, no change was seen in their functional capacity for promoting cytokine production. In ovo supplementation with thymulin partially reversed lead-induced DTH depression without any change in IFN-gamma-like cytokine production. Embryonic exposure to thymulin alone partially depressed the DTH response.. These results suggest that lead can directly influence thymocyte function in the absence of the thymic microenvironment. Since thymulin levels may influence lead-induced immunotoxicity, embryonic endocrine status may be an important consideration. Lead exposure appears to alter thymic functions directly; however, indirect effects via endocrine factors are not precluded.

Topics: Animals; Body Weight; Cells, Cultured; Chick Embryo; Chickens; Drug Combinations; Embryo, Nonmammalian; Hypersensitivity, Delayed; Immune System; Immunity; Interferon-gamma; Organometallic Compounds; Spleen; Stromal Cells; Teratogens; Thymic Factor, Circulating; Thymus Gland

An Endocrine function of the thymus was studied by analyzing the level of thymulin in rats in 1-6 months after extirpation of the thymus. The level of thymulin in rats after thyroidectomy has been shown to be reduced maximally in 6 months after an operation. An inhibitor of thymulin was detected in the blood serum in a month after extirpation, then it disappeared completely from it. After thyroidectomy the mass of animals decreased, as well as an absolute and relative mass of the thymus and its cellular content. Thyroidectomy was followed with a marked decrease in the thyroid hormones content in the blood serum and a reduce in the adrenal cortex, especially at a distant period following an operation. The data obtained evidence that it is sensible to use the agents of the thymic origin to restore the hormone balance at hypothyroidism, together with the substitute therapy.

Topics: Animals; Body Weight; Disease Models, Animal; Hypothyroidism; Male; Organ Size; Rats; Thymic Factor, Circulating; Thymus Gland; Thyroid Hormones; Thyroidectomy

Growth retardation, thymic involution and impaired peripheral immune efficiency are constant events in piglets exposed to maternal aflatoxicosis. Zinc may play a key role because of its requirement for good immune responses, including thymic endocrine activity. Zinc is required to activate a thymic hormone, i.e. thymulin (ZnFTS), which is responsible for cell-mediated immunity. Zinc deficiency and decreased thymic endocrine activity are present in piglets fed from sows exposed to aflatoxins (AF) B1 and G1 as compared with healthy control piglets. In particular, active ZnFTS is decreased while concentrations of inactive thymulin (FTS) are high. The in vitro addition of zinc up to the plasma samples induces a reduction of inactive thymulin. The lymphocytes mitogen responsiveness (PHA) is decreased and a thymic cortical lymphocyte depletion is also present. These data suggest that the thymic defect, followed by impaired peripheral immune efficiency, may largely depend by the low peripheral zinc bioavailability to saturate all thymulin molecules produced.

Topics: Aflatoxin B1; Aflatoxins; Animals; Body Weight; Chromatography, High Pressure Liquid; Female; Lymphocyte Activation; Male; Maternal-Fetal Exchange; Milk; Mycotoxicosis; Organ Size; Phytohemagglutinins; Pregnancy; Swine; Swine Diseases; T-Lymphocytes; Thymic Factor, Circulating; Thymus Gland; Zinc

Links between zinc and melatonin in old melatonin treated mice with a reconstitution of thymic functions have been recently documented. Concomitant increments of the nocturnal peaks of zinc and melatonin, with a synchronization of their circadian patterns, are achieved in old mice after melatonin treatment. A recovery of the nocturnal peaks of thymulin plasma levels and of the number of thymulin-secreting cells with a synchronization of their circadian patterns are also achieved. The existence of significant positive correlations between melatonin and zinc and between melatonin and thymulin or the number of thymulin-secreting cells supports the presence of links between zinc and melatonin also during the circadian cycle with a beneficial effect on thymic functions. The altered circadian pattern of corticosteron in old mice is normalized by melatonin. The existence of inverse correlations between corticosteron and melatonin, between corticosteron and zinc and between corticosteron and thymulin or the number of thymulin-secreting cells during the whole circadian cycle, suggests the involvement of glucocorticoids pathway in the melatonin thymic reconstitution, via zinc. The presence of an interplay among zinc, melatonin, glucocorticoids and thymulin may be, therefore, supported during the circadian cycle. 'In vitro' experiments from old thymic explants show a direct action of zinc, rather than melatonin, on thymulin production, further suggesting that the action of melatonin on the thymic efficiency is mediated by the zinc bioavailability. The beneficial effect of the links between zinc and melatonin on thymic functions during the circadian cycle, may be extended to a prolonged survival in aging, where, however, zinc may be more involved.

Topics: Aging; Animals; Antioxidants; Body Weight; Cells, Cultured; Circadian Rhythm; Corticosterone; Male; Melatonin; Mice; Mice, Inbred BALB C; Neurosecretory Systems; Receptors, Cell Surface; Receptors, Cytoplasmic and Nuclear; Receptors, Melatonin; Survival Analysis; Thymic Factor, Circulating; Thymus Gland; Zinc

Melatonin (MEL) affects the immune system by direct or indirect mechanisms. An involvement of the zinc pool in the immune-reconstituting effect of MEL in old mice has recently been documented. An altered zinc turnover and impaired immune functions are also evident in pinealectomized (px) mice. The present work investigates further the effect of "physiological" doses of MEL on the zinc pool and on thymic and peripheral immune functions in px mice. Daily injections of MEL (100 micrograms/mouse) for 1 month in px mice restored the crude zinc balance from negative to positive values. Thymic and peripheral immune functions, including plasma levels of interleukin-2, also recovered. The nontoxic effect of MEL on immune functions was observed in sham-operated mice. Because the half-life of MEL is very short (12 min), interruption of MEL treatment in px mice resulted, after 1 month, in a renewed negative crude zinc balance and a regression of immune functions. Both the zinc pool and immunological parameters were restored by 30 further days of MEL treatment. The existence of a significant correlation between zinc and thymic hormone after both cycles of MEL treatment clearly shows an involvement of the zinc pool in the immunoenhancing effects of MEL and thus suggests an inter-relationship between zinc and MEL in px mice. Moreover, the existence of significant positive correlations between zinc or thymulin and interleukin-2 suggests that interleukin-2 may participate in the action of MEL, via zinc, on thymic functions in px MEL-treated mice.

Topics: Analysis of Variance; Animals; Body Weight; Male; Melatonin; Mice; Mice, Inbred BALB C; Pineal Gland; Thymic Factor, Circulating; Thymus Gland; Zinc

To define the effects of iron deficiency on thymulin biological activity, T-cell subsets, and thymocyte proliferation, C57BL/6 female mice at weaning were fed an iron-deficient diet (10 mg Fe/kg diet), an iron-sufficient diet (50 mg Fe/kg diet), or restricted amounts of the iron-sufficient diet (the pair-fed group) for 40 d. Iron deficiency did not reduce the concentration of either serum or intracytoplasmic thymulin. Although T-cell subsets in the thymus were not altered, both the cortical and medullar regions were depleted of thymocytes. In the spleen iron deficiency (but not underfeeding) significantly reduced the percentage of L3T4+ cells, of Lyt-2+ cells, and thus of the overall T-cell population. However, it did not affect the ratio of L3T4+ to Lyt-2+ T cells. Thymocyte proliferation was significantly reduced at the concanavalin A (Con A) dose (10 mg/L) that produced maximal stimulation in control and pair-fed mice but not at low (7.5 mg/L) or high (15 mg/L) Con A concentrations. We conclude that the impairment in immune functions associated with iron deficiency is not due to an impairment in thymic endocrine function but rather to decreased immunocompetent lymphocytes.

Topics: Anemia, Hypochromic; Animals; Antibody Formation; B-Lymphocytes; Body Weight; Cell Division; Diet; Female; Immunity, Cellular; Mice; Mice, Inbred C57BL; Nutritional Status; Organ Size; T-Lymphocytes; Thymic Factor, Circulating; Thymus Gland; Thymus Hormones

The volume of epithelium in the cortex and in the medulla of the thymus was compared in four groups of weanling male and female CBA/J mice. Well-nourished controls (C), food intake restricted (R), and animals given a low-protein diet ad libitum (LP) were fed from 23 to 37 days of age. Baseline controls (B) were studied at 23 days of age. Epithelial volume fraction was estimated for each group by point-counting morphometry on electron micrographs. Other mice were used to obtain group mean estimates of thymic index (mg/g live weight) and volume fraction of cortex and medulla (light microscope-level point-counting morphometry). Cortical and medullary epithelial volumes were calculated for each animal examined by electron microscopy by obtaining the live weight and applying, in sequence, the group mean thymic index, an assumed thymic density of 1.0 mm3/mg, the group mean cortical or medullary volume fraction, and the measured cortical or medullary volume fraction for that animal. Serum thymulin bioactivity was also measured in C, R, and LP mice. The results reveal thymic epithelial involution in the two most common rodent models of malnutrition, and suggest that this may contribute to the low serum thymulin levels found in malnourished experimental animals and humans.

Topics: Animals; Body Weight; Epithelium; Female; Food Deprivation; Male; Mice; Mice, Inbred CBA; Organ Size; Protein Deficiency; Thymic Factor, Circulating; Thymus Gland; Thymus Hormones

Thymulin (or FTS-Zn) a well-defined thymic hormone was studied in fifteen female patients hospitalized for anorexia nervosa. The circulating hormone was measured together with the plasma levels of thyroid hormones, cortisol and zinc. Thymulin activity determined by the rosette assay was significantly reduced in the anorexia nervosa patients compared to sex- and age-matched healthy control subjects. The patients were characterized by very depressed plasma levels of triiodothyronine (T3) but exhibited normal concentrations of thyroxine (T4), thyroxine-binding globulin (TBG), cortisol and zinc. The distribution of their peripheral lymphocyte cells into several subsets was not affected. The observed decrease of thymulin activity in this illness might be the consequence of thymic atrophy secondary to malnutrition and/or hormonal disturbances. Our results suggested that the fall in thymulin level might explain the variability of cellular immune responses in anorexia nervosa patients and occurrence of energy when their weight loss is far advanced.

Topics: Adolescent; Adult; Anorexia Nervosa; Body Height; Body Weight; Female; Humans; Hydrocortisone; Leukocyte Count; T-Lymphocytes; Thymic Factor, Circulating; Thymus Hormones; Thyroxine; Thyroxine-Binding Proteins; Triiodothyronine; Zinc

Thymulin (or serum thymic factor, FTS-Zn), a well-defined thymic hormone previously shown to be a nonapeptide binding the metal zinc, was studied in mice subjected to a long-term marginally Zn-deficient diet. In spite of the absence of thymic atrophy, we observed a significant decrease in the serum levels of thymulin as early as two months after the onset of treatment. However, these levels could be consistently restored after in vitro addition of ZnCl2. The analysis of thymuses from Zn-deficient mice showed that, despite the apparently normal network of epithelial cells, there was a progressive increase in the number of thymulin -containing cells (assessed by immunofluorescence with anti- thymulin monoclonal antibodies) that was already significant after two months of treatment. These results are in keeping with those of previous investigators, showing a specific, altered, thymic endocrine function following Zn deprivation. Nonetheless, our results strongly suggest that the nonactive Zn-deprived peptide is secreted under these experimental conditions. Furthermore, the fact that the augmented numbers of thymulin -containing cells were observed in the thymuses following a decrease in the peripheral thymulin (biologically active) brings further evidence for the existence of a feedback mechanism for the secretion of this hormone.

Topics: Animals; Azathioprine; Body Weight; Female; Mice; Mice, Inbred C57BL; Organ Size; T-Lymphocytes; Thymic Factor, Circulating; Thymus Gland; Thymus Hormones; Time Factors; Zinc