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Biomedical subjects

I Oswald

Publications and source records attributed to I Oswald.

At least 19 recordsLinked to original sources
PubMed2000

Inhibitory activity of anti-interleukin-4 and anti-interleukin-10 antibodies on Toxoplasma gondii proliferation in mouse peritoneal macrophages cocultured with splenocytes from infected mice.

Cocultures of splenocytes from Toxoplasma gondii-immunized mice or from naive mice, separated by a transwell membrane from naive macrophage layers, induced a decrease in T. gondii proliferation in macrophages in comparison with cultures without splenocytes or cocultures with splenocytes from infected mice. Interleukin 4 (IL-4) and IL-10 levels increased in cocultures of splenocytes from infected mice with naive macrophages. In contrast, the levels of these cytokines decreased in cocultures with splenocytes from immunized mice. No correlation was found between the release of interferon-gamma (IFN-gamma) and the inhibition of parasite multiplication. Cocultures with splenocytes from immunized mice induced an increase in tumor necrosis factor-alpha (TNF-alpha) levels. In contrast, in cocultures with splenocytes from infected mice, TNF-alpha production decreased. In cocultures with splenocytes from infected mice, T. gondii proliferation in macrophages was neutralized by anti-IL4 or anti-IL10 antibodies and was associated with increased TNF-alpha production. Moreover, this study demonstrates the significant combined effect of IL-4 and IL-10 on the down-regulation of macrophage-effector functions. A soluble positive signal was given by splenocytes to induce the production of TNF-alpha by macrophages. This signal was inhibited by IL4 and IL10. This process is biologically relevant in the regulation of T. gondii proliferation.

Animals↗
PubMed2000

Two isostructural triboluminescent lanthanide complexes.

(4-Dimethylaminopyridine)tris(2,2,6,6-tetramethylheptane-3, 5-dionato)terbium(III), [Tb(C(11)H(19)O(2))(3)(C(7)H(10)N(2))], and its samarium analogue, [Sm(C(11)H(19)O(2))(3)(C(7)H(10)N(2))], are isostructural. Their polar space group is consistent with observed second harmonic generation and with the involvement of piezoelectric charging in their intense triboluminescence properties, which are of interest for the development of damage sensors in composite materials. The metals display irregular seven-coordination by one substituted pyridine and three chelating diketonate ligands, bond lengths to Tb being shorter than those to Sm.

Journal Article↗
PubMed1995

Vaccination routes that fail to elicit protective immunity against Schistosoma mansoni induce the production of TGF-beta, which down-regulates macrophage antiparasitic activity.

C57BL/6 mice immunized intradermally (i.d.) with bacillus Calmette Guerin (BCG) plus killed skin-stage schistosomula are protected against subsequent infection with Schistosoma mansoni, whereas immunization by i.v. or i.m. routes is not protective. Moreover, previous immunization via the nonprotective i.v. route interfered with the ability to subsequently induce protection by i.d. vaccination, suggesting that inhibitory responses are invoked. Given the evidence that activated macrophages (M phi) play a role as effector cells in protection against schistosomiasis, we investigated the ability of spleen cells from protected and nonprotected immunized mice to produce M phi activating and deactivating cytokines. Exposure to supernatant fluids (SNs) from Ag stimulated spleen cells of i.d., but not i.v. or i.m., immunized mice activated inflammatory M phi for in vitro killing of schistosome larvae, through a mechanism dependent on both IFN gamma and TNF-alpha. No evidence was observed for the preferential induction of the M phi activating Th1 cytokines IFN-gamma and IL-2 in i.d. immunized mice, nor did spleen cells from nonprotected animals produce higher levels of the Th2 associated cytokines IL-4 and IL-10, which are known to prevent M phi activation. TGF-beta was, however, detected in SNs from unprotected mice. Moreover, the M phi inhibitory activity detected in these SNs was heat stable and neutralized by anti-TGF-beta Abs, suggesting that production of TGF-beta is at least partially responsible for the failure of i.m. and i.v. immunized mice to develop immunity to S. mansoni. Thus, the induction of down-regulatory cytokines may be an important factor limiting the efficacy of certain vaccination protocols.

Animals↗
PubMed1994

Demonstration of the target molecule of a protective IgE antibody in secretory glands of Schistosoma japonicum larvae.

We have demonstrated that a mouse monoclonal IgE antibody, SJ18 epsilon.1, recognizes a 97 kDa surface molecule (Sj97) of Schistosoma japonicum larvae and that the antibody induces partial but significant protection against the skin to lung-stage of S. japonicum infection. The antibody stimulates eosinophil- and macrophage-mediated killing of schistosomula in vitro. In the present study, we isolated the putative full-length cDNA of Sj97 by screening a lambda gt11 cDNA library from S. japonicum adult worms with SJ18 epsilon.1. The predicted amino acid sequence of the cDNA showed highly significant homology to that of S. mansoni paramyosin, a potential vaccine candidate for schistosomiasis. The deletion mutants of S. japonicum paramyosin were expressed in Escherichia coli and the translation product of 443 amino acid residues of paramyosin was found to be recognized by the antibody. Moreover, we observed by immunoelectron microscopy the presence of paramyosin in the post-acetabular gland as well as in the tegument and muscle layers of the larvae. These results suggest that paramyosin is a secretory protein which may be incorporated into the tegument during the development of schistosomula, thus becoming a target for protective immunity during the migratory phase of the parasite.

Amino Acid Sequence↗
PubMed1991

Hypnotics and sleep physiology: a consensus report. European Sleep Research Society, Committee on Hypnotics and Sleep Physiology.

The effects of hypnotics on descriptive and functional aspects of electrophysiological sleep parameters are assessed in this report. Because of the arbitrary definition of some of the criteria underlying the conventional sleep stage scoring procedure, computer-aided methods of EEG analysis have become increasingly important for recording and interpreting pharmacological effects on sleep. Of particular interest are the changes of EEG slow-wave activity, since this parameter varies as a function of prior sleep and waking. Several types of interaction between hypnotics and sleep regulation are discussed, some recent pharmacological developments are highlighted, and some common problems in clinical trials are specified.

Anti-Anxiety Agents↗
PubMed1989

Effects of repeated ritanserin on middle-aged poor sleepers.

Nine subjects who believed themselves to be poor sleepers, of mean age 58 years, took a placebo for 7 days, then ritanserin 5 mg for 20 days, followed by 3 days on placebo. Sleep was recorded electrophysiologically on 2 nights during baseline, 2 early drug nights, 2 late drug nights and the 2nd and 3rd withdrawal nights. Ratings of sleep quality were collected each morning. Ritanserin, a 5HT2 antagonist, caused a persistent doubling of the amount of EEG slow wave sleep, without altering the total duration of sleep. Ritanserin decreased the frequencies of awakening and after about a week it appeared to improve the subjective quality of sleep. Sleep was then impaired during withdrawal, as indicated by decreased duration and poorer subjective quality, being worst on the 3rd withdrawal night.

Attention↗
PubMed1989

Can a rapidly-eliminated hypnotic cause daytime anxiety?

To test further the conclusions of preliminary reports that regular use of a rapidly-eliminated hypnotic might cause daytime anxiety, 82 women and 38 men, mean age 53, who claimed to be poor sleepers, took a capsule nightly for 45 nights. On 25 consecutive nights the capsule contained triazolam 0.5 mg (40 subjects), lormetazepam 2 mg (40 subjects) or continued placebo (40 subjects). Both drugs improved sleep, but compared with placebo or lormetazepam-takers, triazolam-takers became more anxious on self-ratings, were judged more often to have had a bad response by an observer, more often wrote down complaints of distress, and suffered weight loss. After about 10 days of regular triazolam they tended to develop panics and depression, felt unreal, and sometimes paranoid. The very short life of triazolam, leading to daytime withdrawal symptoms, may account for some of the observations, but enhancement of benzodiazepine inverse agonist activity is also hypothesized.

Adult↗