Inclusion of silver nanoparticles for improving regenerated cellulose membrane performance and reduction of biofouling

The preparation of silver nanoparticles (AgNPs) and their incorporation into the structure of a regenerated cellulose membrane by dip coating is presented. Morphological characterization of the AgNPs (average diameter of 20±2nm) was carried out by SEM/TEM, while elastic, electrical and antimicrobial properties of the hybrid membrane were also analyzed. The presence of silver nanoparticles in the membrane seems to increases its rigidity and its chemical stability against oxidation, but it only induces small changes in the transport parameters. As expected, AgNPs provide antimicrobial properties to the membrane and consequently the reduction of biofouling without affecting significantly other characteristic parameters, opening the application of the modified membrane to wastewaters treatment.

The hypothalamic-pituitary-thyroid axis and melatonin in humans: possible interactions in the control of body temperature

OBJECTIVE

Melatonin plays a role in the regulation of biological rhythms, body temperature presents circadian variations with lower levels during nighttime, when melatonin levels are very high, and thyroid hormones influence shiver independent thermogenesis. We have investigated on possible interactions between the hypothalamic-pituitary-thyroid axis and melatonin in the control of body temperature in humans.

METHODS

Peripheral blood samples for thyrotropin-releasing hormone (TRH), thyroid-stimulating hormone (TSH), free-thyroxine (FT4), melatonin levels determination and body temperature measurements were obtained every four hours for 24-hours starting at 0600 h in a controlled temperature and light-dark environment from ten healthy males, aged 38-65 (mean age +/-s.e. 57.4+/-3.03, mean body mass index +/-s.e. 25.5+/-0.75). We calculated fractional variation and correlation on single time point hormone serum levels and tested whether the time-qualified data series showed consistent pattern of circadian variation.

RESULTS

A statistically significant difference was evidenced for the fractional variation of daytime TSH serum levels (0600 h-1000 h vs. 1000 h-1400 h, p=0.01, 1000 h-1400 h vs. 1400 h-1800 h, p=0.0001, 1400 h-1800 h vs. 1800 h-2200 h, p=0.001) and for the fractional variation of FT4 serum levels at 1800 h-2200 h vs. 2200 h-0200 h (p=0.02). FT4 serum levels correlated positively with TRH serum levels at 1000 h (r=0.67, P=0.03) and at 1400 h (r=0.63, p=0.04), negatively with TSH serum levels at 2200 h (r=-0.67, p=0.03), negatively with melatonin serum levels at 2200 h (r=-0.64, p=0.04) and at 0200 h (r=-0.73, p=0.01). TRH serum levels correlated positively with TSH serum levels at 0200 h (r=0.65, p=0.04) and at 0600 h (r=0.64, p=0.04). Body temperature correlated positively with FT4 serum levels at 1000 h (r=0.63, p=0.04) and negatively with melatonin serum levels at 0200 h (r=-0.64, p=0.04). A clear circadian rhythm was validated for body temperature (with acrophase in the morning) and melatonin, TRH and TSH secretion (with acrophase at night), while FT4 serum level changes presented ultradian periodicity (with acrophase in the morning).

CONCLUSION

Changes of TSH serum levels are smaller and those of FT4 are greater at night, when melatonin levels are higher, so that the response of anterior pituitary to hypothalamic TRH and of thyroid to hypophyseal TSH may be influenced by the pineal hormone that may modulate the hypothalamic-pituitary-thyroid axis function and influence the circadian rhythm of body temperature.

Immune system alterations in lung cancer patients

The immune system plays an important role in the defense against neoplastic disease and immune responses show temporal changes related to circadian variations of antibodies, total lymphocytes in the peripheral blood and cell mediated immune responses. In this study we evaluate. lymphocyte subpopulations and interleukin-2 (IL-2) serum levels in peripheral blood samples collected at four-hour intervals for 24-hours starting at 06.00 h from ten healthy subjects aged 65-79 years (mean age +/- s.e. 67.28 +/- 3.11) and from ten subjects suffering from untreated non small cell lung cancer aged 65-78 years (mean age +/- s.e. 68.57 +/- 1.81). Areas under the curve, mean diurnal levels (mean of 06.00-10.00-14.00 h) and mean nocturnal levels (mean of 18.00-22.00-02.00 h) were calculated, and the presence of circadian rhythmicity was evaluate. When we compared AUC values there was a decrease in CD8bright (T suppressor subset) and an increase in CD16 (natural killer cells) and of IL-2 serum levels in cancer patients. When we compared mean diurnal levels, CD8 (T suppressor/cytotoxic subset) and CD8bright levels were lower, and CD16 levels were higher in cancer patients. When we compared mean nocturnal levels, CD16 and CD25 (T and B activated lymphocytes with expression of the a chain of IL-2 receptor) levels were higher, while CD8, CD8bright, CD20 (total B-cells), TcRd1 (epitope of the constant domain of d chain of T-cell receptor 1) and dTcS1 (epitope of the variable domain of d chain of T-cell receptor1) levels were lower in cancer patients. A clear circadian rhythm was validated for the time-qualified changes in CD4, CD20, HLA-DR with acrophase at night, and CD8, CD8 bright, CD8 dim, CD16, TcRd1 and dTcS1 with acrophase in the morning in the control group. A clear circadian rhythm was validated for the time-qualified changes in CD4 with acrophase at night, in the group of cancer patients. Results obtained in our study show that lung cancer is associated with anomalies of proportion and circadian variations of lymphocyte subsets that must be considered when adoptive immunotherapy has to be planned.