The sociospatial diversity in the leisure activities of older people in the Netherlands.

Leisure activities afford an important way for old people to continue to take part in society and have a positive effect on personal wellbeing. The types and number of leisure activities in which older people participate are highly diverse. This diversity is associated not only with personal characteristics, but also with those of the environment in which old people live. Using cross sectional data selected in 2002-2003, differences are presented between regions, cities and villages, and between prosperous and deprived neighbourhoods. The characteristics of the region and of the urban or rural environment show a clear relationship wit the intrinsic orientation in leisure. The diversity is smallest among older adults who live in deprived neighbourhoods and among the very old. They take part in fewer activities (contraction), which leads to a more similar activity pattern in and around the home (convergence).

Chronic stimulation of the hypothalamus-pituitary-adrenal axis in rats by interleukin 1beta: central and peripheral mechanisms.

The authors have studied mechanisms which could be involved in the sustained activation of the hypothalamus-pituitary-adrenal (HPA) axis during continuous infusion of rats with recombinant human interleukin-1beta (IL-1beta). First, the effects of 3 days of intracerebroventricular (i.c.v.) infusion of rats with IL-1 on plasma adrenocorticotropin (ACTH) and corticosterone (B) levels were investigated. Thereafter, changes in plasma ACTH and B levels were followed in rats intraperitoneally (i.p.) infused with IL-1beta after immunoneutralization of corticotropin-releasing hormone (CRH), hypophysectomy (HPX), macrophage depletion using dichloromethylene diphosphonate (Cl2MDP)-containing liposomes, adrenalectomy (ADX) and dexamethasone (DEX) administration, respectively. Infusion of IL-1beta i.c.v., even in doses as low as 0.1 microg/day, induced significant increases in plasma ACTH and B levels. HPX and ADX rats died within 18 h after starting the IL-1beta infusion (0.5 microg/day). Immunoneutralization of CRH significantly decreased and macrophage depletion significantly increased the stimulation of the HPA axis by IL-1 (4.0 microg/day). Administration of high doses of DEX completely abolished the stimulation of the HPA axis by IL-1beta (2.0 microg/day). The present study demonstrates that lower doses of IL-1beta were able to activate the HPA axis when infused i.c.v. compared with i.p. Regarding stimulation of the HPA axis by chronic i.p. infusion of IL-1beta the present study: (1) provides evidence that the CRH system is involved; (2) provides no evidence for a direct stimulatory effect of IL-1beta on the release of B by the adrenal gland which is of sufficient magnitude to resist the stress of chronic i.p. IL-1beta infusion; (3) shows that endogenous macrophage-derived mediators, induced by i.p. IL-1beta infusion, express an overall inhibitory rather than a stimulatory effect on the activity of the HPA axis; (4) demonstrates that exogenous administration of DEX blocks the effect of IL-1beta, which fits well in the concept of an immunoregulatory feedback between IL-1beta and glucocorticoids.

Pharmacokinetics and bioavailability of tamoxifen in postmenopausal healthy women.

A randomised cross-over study in 24 postmenopausal women was selected to establish bioequivalence of two tamoxifen (CAS 10540-29-1) formulations. In addition, this study compiled pharmacokinetic parameters for the current 30 mg regimen in postmenopausal women, the target population of tamoxifen therapy. Mean Cmax values of 59.1 +/- 8.9 (T) and 63.6 +/0 11.1 (R) ng/ml were attained 3.6 +/- 1.2 (T) and 3.2 +/- 1.1 (R) h after administration of 30 mg tamoxifen for the test (T) and the reference (R) formulation. The mean AUC (0-480) of tamoxifen was calculated as 3299.7 +/- 761.2 (T) and 3370.1 +/- 701.9 (R) ng x h/ml. The corresponding AUC (0-480) of the active metabolite, N-desmethyl-tamoxifen, exceeded that of the parent drug with 4359.7 +/- 830.5 (T) and 4306.3 +/- 835.2 (R) ng x h/ml, whereas maximal concentrations of the metabolite were distinctly decreased with 14.4 +/- 3.3 (T) and 14.3 +/- 2.4 (R) ng/ml. The pharmacokinetic parameters evaluated in this study are well in line with already known pharmacokinetic data generated with young male volunteers and postmenopausal patients with breast cancer. Precise analytics and an extremely long blood sampling period facilitated an accurate determination of tamoxifen's half-life in postmenopausal women with 210.1 +/- 60.8 (T) and 209.8 +/- 59.9 (R) h. Based on the extremely long half-life, the suitability of a cross-over design is discussed and recommended for further studies.

Effects of cytokines on pituitary beta-endorphin and adrenal corticosterone release in vitro.

We investigated the effects of recombinant human IL-1 alpha, -1 beta, -2, -6 and TNF on the in vitro secretion of beta-endorphin-immunoreactivity (beta E-IR) by the rat anterior and neurointermediate lobes (AL and NIL, respectively) and of B by the rat adrenal gland. Isolated AL and NIL cells were incubated for 2 h with cytokines (1 pg/m1(-1) mu g/ml), CRH (5.10(-10) M) or with cytokines in combination with CRH (AL cells), isolated adrenal cells were incubated for 2 h with cytokines, ACTH (25 pg/ml) or with cytokines in combination with ACTH. Furthermore, AL, NIL and adrenal tissue fragments were superfused for 30 or 60 min with cytokines (10 and/or 100 ng/ml). Incubation of AL, NIL and adrenal cells and superfusion of these tissues with cytokines had no significant effect on beta E-IR and B release. However, there are some exceptions: incubation of AL cells with IL-2 increased CRH-induced beta E-IR release, incubation of NIL cells with IL-2 induced an increase of basal beta E-IR release, ACTH-induced B secretion was reduced after co-incubation of adrenal cells with TNF and after prolonged (6 h) superfusion of adrenal tissue with TNF, and finally, prolonged (6 h) superfusion of adrenal fragments with IL-1 beta increased basal B release. Taken together, these data suggest that the acute activation of the pituitary-adrenal axis of rats by administration of cytokines (at least IL-1, IL-6 and TNF) in vivo is not mediated by a direct action of these cytokines at the level of the pituitary and/or adrenal gland.

Acute stimulation of the hypothalamic-pituitary-adrenal axis by IL-1 beta, TNF alpha and IL-6: a dose response study.

We investigated the effects of i.v. and intracerebroventricular (i.c.v) administration of increasing doses of recombinant human IL-1 beta, TNF alpha and IL-6 on plasma corticosterone (B) levels in rats. Rats were equipped with a jugular cannula for repeated blood sampling anda subgroup of rats also received an i.c.v implanted cannula. I.v. administration of IL-1 beta, TNF alpha or IL-6 and i.c.v administration of IL-1 beta and IL-6 induced a significant dose-dependent increase in plasma B levels, whereas i.c.v injection of TNF alpha in doses up to 1000 ng/rat was not effective. I.v. pretreatment of rats with anti-CRH antiserum had no significant overall effect on the plasma B response to i.v. administered IL-1 beta (500 and 3000 ng/rat), whereas the plasma B response to i.v. TNF alpha or IL-6 administration (3000 ng/rat) were significantly reduced. I.v. pretreatment of the animals with recombinant human IL-1 receptor antagonist (IL-1ra) significantly blocked the plasma B response to i.v. treatment with IL-1 beta, whereas the TNF alpha- and IL-6-induced increases in plasma B levels were not affected. Our data show that 1) i.v. administration of IL-beta, TNF alpha or IL-6 and i.c.v administration of IL-1 beta or IL-6 dose-dependently stimulate the HPA axis; 2) when given i.v. or i.c.v, IL-1 beta is more powerful than TNF alpha and IL-6 in activating the HPA axis; 3) endogenous CRH is involved in the activation of the HPA axis by acute i.v. administration of TNF alpha and IL-6. It is most likely that in case of i.v. treatment with IL-1 beta a CRH-independent mechanism is involved. This study provides no arguments for the involvement of endogenous IL-1 in TNF alpha- or IL-6-induced activation of the HPA axis.

Synergism between IL-1 beta and TNF-alpha on the activity of the pituitary-adrenal axis and on food intake of rats.

We investigated the effects of separate and combined intraperitoneal administration for 3 days of recombinant human interleukin-1 beta (IL-1) and recombinant human tumor necrosis factor-alpha (TNF) on plasma adrenocorticotropic hormone (ACTH) and corticosterone (B) levels, adrenal weight, food intake, and rectal temperature. Rats were equipped with a jugular cannula for daily blood sampling and with an intraperitoneally implanted Alzet osmotic minipump loaded with either saline, IL-1 (2.0 micrograms/day), TNF (0.2, 2.0, or 10.0 micrograms/day), or IL-1 in combination with TNF. Plasma ACTH and B levels and adrenal weight were significantly increased, in a dose-dependent way, by simultaneous infusion of IL-1 and TNF but not by administration of either cytokine alone. Chronic administration of IL-1 alone induced a significant decrease in food intake and a significant elevation of rectal temperature, whereas infusion of only the highest dose of TNF significantly elevated rectal temperature. Coinfusion of IL-1 and TNF induced both effects in a dose-dependent and synergistic way. Our data show that simultaneous infusion of IL-1 and TNF in rats has a synergistic effect on the activity of the pituitary-adrenal axis as well as on food intake and rectal temperature. The existence of two pathways, which act synergistically, may increase the sensitivity of the host to respond to subtle inflammatory stimuli.

Different effects of continuous infusion of interleukin-1 and interleukin-6 on the hypothalamic-hypophysial-thyroid axis.

The cytokines interleukin-1 (IL-1) and IL-6 are thought to be important mediators in the suppression of thyroid function during nonthyroidal illness. In this study we compared the effects of IL-1 and IL-6 infusion on the hypothalamus-pituitary-thyroid axis in rats. Cytokines were administered by continuous ip infusion of 4 micrograms IL-1 alpha/day for 1, 2, or 7 days or of 15 micrograms IL-6/day for 7 days. Body weight and temperature, food and water intake, and plasma TSH, T4, free T4 (FT4), T3, and corticosterone levels were measured daily, and hypothalamic pro-TRH messenger RNA (mRNA) and hypophysial TSH beta mRNA were determined after termination of the experiments. Compared with saline-treated controls, infusion of IL-1, but not of IL-6, produced a transient decrease in food and water intake, a transient increase in body temperature, and a prolonged decrease in body weight. Both cytokines caused transient decreases in plasma TSH and T4, which were greater and more prolonged with IL-1 than with IL-6, whereas they effected similar transient increases in the plasma FT4 fraction. Infusion with IL-1, but not IL-6, also induced transient decreases in plasma FT4 and T3 and a transient increase in plasma corticosterone. Hypothalamic pro-TRH mRNA was significantly decreased (-73%) after 7 days, but not after 1 or 2 days, of IL-1 infusion and was unaffected by IL-6 infusion. Hypophysial TSH beta mRNA was significantly decreased after 2 (-62%) and 7 (-62%) days, but not after 1 day, of IL-1 infusion and was unaffected by IL-6 infusion. These results are in agreement with previous findings that IL-1, more so than IL-6, directly inhibits thyroid hormone production. They also indicate that IL-1 and IL-6 both decrease plasma T4 binding. Furthermore, both cytokines induce an acute and dramatic decrease in plasma TSH before (IL-1) or even without (IL-6) a decrease in hypothalamic pro-TRH mRNA or hypophysial TSH beta mRNA, suggesting that the acute decrease in TSH secretion is not caused by decreased pro-TRH and TSH beta gene expression. The TSH-suppressive effect of IL-6, either administered as such or induced by IL-1 infusion, may be due to a direct effect on the thyrotroph, whereas additional effects of IL-1 may involve changes in the hypothalamic release of somatostatin or TRH.(ABSTRACT TRUNCATED AT 400 WORDS)

Intravenous administration of interleukin-1 beta induces Fos-like immunoreactivity in corticotropin-releasing hormone neurons in the paraventricular hypothalamic nucleus of the rat.

It has been shown that acute administration of recombinant human interleukin 1 beta (IL-1) to rats elicits an activation of the pituitary-adrenal axis. In the present study we investigated immunohistochemically the expression of Fos-like immunoreactivity (Fos-LI) in the hypothalamus of rats following intravenous injection of IL-1. One, 2 and 4 h after IL-1 or physiological saline injections, rats were killed and perfused, and the brains processed for Fos-immunohistochemistry. Dense populations of neurons containing Fos-LI-positive nuclei were found in the paraventricular hypothalamic nuclei (PVH) of IL-1-treated rats. In particular, the dorsal medial parvocellular part, but also some of the other parvocellular subdivisions contained many Fos-LI neurons. Maximal induction of staining was found at a dose of 5 micrograms/rat after 1 or 2 h survival, while immunostaining had decreased to almost control levels after 4 h. No Fos-LI was found in the PVH of control animals. Double immunocytochemical staining for Fos and corticotropin-releasing hormone (CRH) revealed that Fos-LI was predominantly present in parvocellular CRH-containing neurons of the PVH. The finding that peripherally injected IL-1 induces Fos-LI in hypothalamic CRH neurons strengthens the hypothesis that these neurons are part of the circuitry mediating IL-1-induced activation of the pituitary-adrenal axis.

Chronic infusion of TNF-alpha reduces plasma T4 binding without affecting pituitary-thyroid activity in rats.

In the present study the effects of continuous administration of tumor necrosis factor-alpha (TNF-alpha), in a dose not affecting body temperature and food intake, on pituitary-thyroid function of rats were investigated. Male rats, bearing a venous catheter to allow repeated blood sampling, were intraperitoneally equipped with osmotic minipumps that continuously delivered recombinant human TNF-alpha (8.0 micrograms/day ip) or saline for 7 days. Infusion of TNF-alpha resulted in a significant decrease of plasma total thyroxine (T4) levels during days 2-5 of infusion as compared with the levels in saline-infused rats. This suppression of plasma T4 concentrations was caused by a decreased binding of T4 in plasma, as indicated by an increased percentage of free T4. TNF-alpha infusion did not significantly affect free T4 levels in plasma nor basal and thyrotropin-releasing hormone-stimulated TSH levels. The decreased binding of T4 was, at least partially, caused by a reduction of T4-binding prealbumin (TBPA) levels in plasma, which were significantly reduced during the first 3 days of TNF-alpha infusion. Plasma levels of free fatty acids were not affected by TNF-alpha. TNF-alpha treatment did not influence the plasma 3,5,3'-triiodothyronine (T3)-to-T4 ratio nor hepatic 5'-deiodinase activity. Plasma reverse T3 levels remained undetectable both in control and TNF-alpha-treated rats. Taken together, our findings indicate that chronic infusion of rats with TNF-alpha in a subpyrogenic and subanorectic dose induces a transient decrease of plasma T4 binding without affecting pituitary-thyroid activity and peripheral thyroid hormone metabolism.(ABSTRACT TRUNCATED AT 250 WORDS)

Continuous infusion of interleukin-1 beta induces a nonthyroidal illness syndrome in the rat.

We studied the effects of continuous administration of recombinant human interleukin-1 beta (IL-1) on pituitary-thyroid function. Rats were equipped with minipumps loaded with either IL-1 (delivery rate, 0.5, 2.0, or 4.0 micrograms/day, ip, for 1 week) or saline. Infusion of 2.0 and 4.0 micrograms IL-1/day caused a significant decrease in plasma free T4 levels during the first 2-4 days, whereas plasma total T4 levels and T4 binding were significantly lowered throughout the week of the study. The infusion of 0.5 micrograms IL-1/day did not significantly change plasma TSH or total and free T4 levels. During the infusion of 2.0 micrograms IL-1/day, the decrease in plasma free T4 levels was paralleled by a significant decline in plasma TSH values and an impaired TSH responsiveness to TRH administration on the second day of infusion. IL-1 (2.0 micrograms/day) treatment significantly lowered plasma levels of T4-binding prealbumin, whereas it did not influence the plasma T3/T4 ratio or hepatic 5'-deiodinase activity. Plasma rT3 levels remained undetectable in both control and IL-1-treated rats. Chronic infusion of rats with 4.0 micrograms IL-1/day induced prolonged fever, whereas at the lower doses of IL-1, temperatures were elevated only on the first 2 days. IL-1 at doses of 2.0 and 4.0 micrograms/day induced a transient decrease in food intake and a suppression of body weight gain. Restriction of food consumption to the level observed in the 2.0 micrograms IL-1 experiment caused small decreases in T3, total and free T4, and TSH levels compared to those in ad libitum fed rats, but had no effects on T4 binding. We conclude that 1) continuous infusion of rats with 2.0 and 4.0 micrograms IL-1/day induces changes in thyroid economy commonly seen during infectious diseases and other systemic illnesses in rats [decreased plasma levels of TSH, T3, and (free) T4; diminished T4 binding; and decreased plasma T4-binding prealbumin levels], 2) the decrease in food intake during IL-1 treatment cannot completely explain the observed changes in thyroid hormone and TSH levels; and 3) it is highly unlikely that the decrease in thyroid hormone binding during chronic IL-1 infusion is caused by decreased food intake. Further studies are needed to clarify whether the observed alterations in thyroid economy during IL-1 infusion reflect direct effects of IL-1 per se or indirect effects caused by the mild illness induced by the cytokine.

Chronic intraperitoneal infusion of low doses of tumor necrosis factor alpha in rats induces a reduction in plasma triglyceride levels.

Single and repeated bolus injections of tumor necrosis factor alpha (TNF) in laboratory animals have been reported to result in hypertriglyceridaemia, suggesting that TNF is a mediator of hypertriglyceridaemia occurring during infection. However, as during infection production of TNF is probably chronically elevated, we determined the effects of continuous infusion of low doses of TNF on plasma levels of triglycerides and cholesterol. Male rats, bearing a venous catheter to allow repeated blood sampling, were intraperitoneally equipped with osmotic minipumps which continuously delivered TNF or saline for 7 days. Infusion of rats with doses of TNF as low as 4.0 and 8.0 micrograms/24 h resulted in significant decreases in plasma levels of triglycerides as compared with those after saline infusion. Although plasma triglyceride concentrations were persistently lower in TNF than in saline animals throughout the study period, the differences were most prominent during the first days and reached statistical significance at day 1, 3, 4 and 5 and of the 4.0 micrograms experiment and on day 1, 2 and 3 of the 8.0 micrograms experiment. This suppression of plasma triglyceride concentrations was not accompanied by changes in plasma cholesterol levels. No effects of chronic TNF treatment on food intake, body weight change and rectal temperature of the animals were observed. These findings indicate that chronic infusion of low doses of TNF induces hypotriglyceridaemia in rats. The role of TNF as a factor in mediating hypertriglyceridaemia during infectious diseases needs to be reconsidered.

Continuous infusion of interleukin-1 beta in rats induces a profound fall in plasma levels of cholesterol and triglycerides.

During infectious diseases, striking alterations in plasma concentrations of cholesterol (hypocholesterolemia) and triglycerides (hypertriglyceridemia) may occur. It has been suggested that interleukin-1 is a mediator of these alterations. We studied the effects of continuous administration of recombinant human interleukin-1 beta (rhIL-1 beta) on plasma levels of cholesterol and triglycerides. A total of 42 rats were equipped with minipumps loaded with either rhIL-1 beta (delivery rate of 0.5, 2.0, or 4.0 micrograms/day i.p. for 1 week) or saline. After 1 day of treatment with rhIL-1 beta, plasma cholesterol levels had not changed. On day 2 a remarkable decrease of plasma cholesterol levels was observed in rats treated with 2.0 micrograms rhIL-1 beta/day (1.49 +/- 0.13 versus 2.23 +/- 0.08 mmol/l, p less than 0.005; rhIL-1 beta versus saline) or 4.0 micrograms rhIL-1 beta/day (1.46 +/- 0.04 versus 2.18 +/- 0.04 mmol/l,p less than 0.0005). This decrease persisted until the end of the experiment and occurred in all major lipoprotein fractions. Triglycerides in plasma (and in very low density lipoprotein) decreased almost concomitantly with plasma cholesterol, although to a lesser degree. Infusion of 2.0 micrograms rhIL-1 beta/day did not affect either cholesterol esterification or total postheparin lipolytic activity in plasma. Long-term infusion with 4.0 micrograms rhIL-1 beta/day induced prolonged fever, whereas at the lower doses temperatures were elevated only the first 2 days. rhIL-1 beta at a dose of 2.0 and 4.0 micrograms/day induced a transient decrease of food intake and a suppression of body weight gain.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic stimulation of the pituitary-adrenal axis in rats by interleukin-1 beta infusion: in vivo and in vitro studies.

It has been shown that acute administration of interleukin-1 (IL-1) to rats elicits a transitory increase in plasma ACTH and corticosterone (B) levels. To investigate the effects of chronic administration of IL-1 on plasma ACTH and B levels, in the present study rats were equipped with Alzet osmotic minipumps loaded with either IL-1 (delivery rate 0.5, 2.0, or 4.0 micrograms/24 h, ip, for 1 week) or saline. At the end of the treatment the rats were decapitated, the adrenals were weighed, and the in vitro release of beta-endorphin (beta E) by the anterior pituitary and that of B by the adrenal gland were measured. Continuous administration of 2.0 and 4.0 micrograms IL-1/24 h resulted in a persistent increase in plasma ACTH and B concentrations compared to the levels in saline-infused rats, with peak levels on the first day of administration. In addition, adrenal weights of IL-1 rats were significantly higher than those of saline rats. The 4.0-micrograms IL-1/day in vivo treatment induced an increase in spontaneous in vitro secretion of beta E and B, while the in vitro responses of the pituitary (to CRF) and the adrenal (to ACTH) of animals treated in vivo with IL-1 were significantly diminished. IL-1 at a dose of 0.5 microgram failed to affect plasma ACTH and B values, adrenal weight, and in vitro beta E and B secretion. Chronic infusion of rats with 4.0 micrograms IL-1/day induced prolonged fever, whereas at lower doses of IL-1 (2.0 and 0.5 micrograms), temperatures were elevated only on the first 2 days of infusion. IL-1 at doses of 2.0 and 4.0 micrograms/day induced suppression of body weight gain on the first 2 days of the treatment period compared to saline treatment. Plasma norepinephrine and/or epinephrine concentrations were raised only on day 1 of the 2.0- and 4.0-micrograms IL-1 experiments. Thus, the observed effects of IL-1 on the hypothalamo-pituitary-adrenal axis probably do not result merely from stress induced by the treatment. Taken together, our data show the potential of IL-1 to induce a dose-dependent and long term activation of the pituitary-adrenal axis.

Comparative bio-availability of theophylline whole and halved sustained-release tablets.

In a randomised, multiple-dose, cross-over study in 14 healthy volunteers, plasma theophylline concentrations were compared during a 12-hour dosing interval after repeated administration of theophylline (Euphyllin Retard; Byk Gulden) as whole and halved tablets. Bio-availability of theophylline from the halved tablets relative to the whole tablets was: 116% (100%, 134%) for the extent of absorption as judged by the area under the concentration time curve (AUC) and 115% (99%, 135%) for the rate of absorption as judged by maximum concentration (Cmax). The confidence levels for the 80-120% bio-equivalence range were 72% (AUC) and 76% (Cmax), those for the 80 and 125% range were 91% (AUC) and 91% (Cmax). The plateau times T75% Cmax, which characterise the sustained-released properties, were 8.5 +/- 2.9 hours (halved) and 8.3 +/- 2.5 hours (whole) during the 12-hour dosing interval. It is concluded that no clinically relevant deviations in steady-state plasma theophylline concentration and sustained-release properties are likely to result from breaking (halving) the film-coated tablets.

The metabolism of atropine in man.

A metabolic pattern of atropine in man, based on the detection of radiolabelled products in urine by high performance liquid chromatography after administration of [3H]atropine sulphate to a normal volunteer is proposed. Noratropine (24%), atropine-N-oxide (equatorial isomer) (15%), tropine (2%) and tropic acid (3%) appear to be the major metabolites, while 50% of the administered dose is excreted as apparently unchanged atropine. No conjugates were detectable. Evidence that atropine is present as (+)-hyoscyamine was found, suggesting that stereoselective metabolism of atropine probably occurs.

Inhibition of atropine metabolism by organophosphate pesticides.

Urine specimens of 8 organophosphate-poisoned patients on treatment with large doses of atropine were screened for atropine metabolites using thin-layer chromatography. Only atropine was detected. High performance liquid chromatography of urine specimens of a poisoned patient receiving large doses of atropine likewise detected only 3H-atropine after administration of 30 microCi 3H-atropine-sulphate. In the urine of a normal human volunteer treated with a single dose of 3H-atropine, 5 metabolic products were detected by this method. It is concluded that acute organophosphate-poisoning blocks atropine metabolism by inhibiting the hepatic microsomal enzymes.