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E D'Hondt

Publications and source records attributed to E D'Hondt.

At least 19 recordsLinked to original sources
PubMed2000

Fos induction in the Japanese quail brain after expression of appetitive and consummatory aspects of male sexual behavior.

We investigated the expression of Fos, the protein product of the immediate early gene c-fos in the brain of male Japanese quail after they engaged in either appetitive or consummatory sexual behavior (i. e., copulation). For 1 h, castrated males treated with testosterone were either allowed to copulate with a female or to exhibit a learned social proximity response indicative of appetitive sexual behavior. Control birds were either left in their home cage or placed in the experimental chamber but did not exhibit the appetitive sexual behavior because they had never learned it. Fos expression was studied with an immunocytochemical procedure in two sets of adjacent sections through the entire forebrain. These sections were immunolabelled with 2 different antibodies raised against a synthetic fragment corresponding to the 21 carboxy-terminal residues of the chicken Fos sequence. Contrary to the results of a previous study in which gonadally intact birds were used, Fos induction was observed neither in the medial preoptic nucleus nor in the nucleus intercollicularis in birds that had interacted for 1 h with a female. This may be related to a lower frequency of copulation in the testosterone-implanted birds than in intact birds, or to differences in the time the brains were collected after the birds engaged in sexual behavior between the two studies (60 min in this study, 120 min in the previous study). The performance of copulation and/or appetitive sexual behavior increased the number of Fos-immunoreactive cells in the ventral hyperstriatum, medial archistriatum, and nucleus striae terminalis. These increases were observed using both antibodies, although each antibody produced minor differences in the number of Fos-immunoreactive cells observed. Using one of the antibodies, but not the other, increases in Fos immunoreactivity were also observed in the nucleus accumbens and hyperstriatum after either copulation or appetitive sexual behavior. These differences illustrate how minor technical variations in the Fos immunocytochemical procedure influence the results obtained. These differences also show that Fos induction in a number of brain regions is observed after performance of consummatory (copulation) as well as appetitive (looking at the female) sexual behavior. This induction is, therefore, not related solely to the control of copulatory acts but, presumably, also to the processing in a variety of telencephalic association areas of stimuli originating from the female. The observation that increased Fos immunoreactivity is present in birds that had learned the response indicative of appetitive sexual behavior, and not in those that had not learned the behavior, further indicates that it is not simply the sight of the female that results in this Fos induction, but the analysis of the relevant stimuli in a sexually explicit context. Conditioned neural activity resulting from a learned association between the stimulus female and the performance of copulatory behavior may also explain some aspects of the brain activation observed in birds viewing, but not allowed to interact with, the female.

Analysis of Variance↗
PubMed2000

Colocalization of arginine-vasotocin and chicken luteinizing hormone-releasing hormone-I (cLHRH-I) in the preoptic-hypothalamic region of the chicken.

To characterize a possible relationship between chicken luteinizing hormone-releasing hormone-I (cLHRH-I) and arginine-vasotocin (AVT) we performed immunocytochemical double-stainings throughout the preoptic-hypothalamic region of the chicken brain. This study clearly reveals a partial colocalization between both neuropeptides. Single-labeled neurons, containing either cLHRH-I or AVT are found intermingled with double stained cells, immunoreactive (ir) for both peptides. A significant number of double-labeled perikarya is found in the preoptic area, more specifically in the ventral and external portion of the supraoptic nucleus (SOv and SOe) and in the medial preoptic nucleus (MPOv). At the level of the anterior hypothalamus, double-labeled cells are predominantly observed near the third ventricle in the nucleus paraventricularis magnocellularis (PVN) and the nucleus periventricularis hypothalami (PHN). Next to this colocalization, a number of cLHRH-I-ir cell bodies are found in close apposition to AVT-ir fiber profiles in the very same areas. Taken together, these data are the first to provide morphological evidence indicating that the AVT system might be involved in the regulation of cLHRH-I release and thus of reproductive functions in birds.

Animals↗
PubMed1999

Validation of a new antiserum directed towards the synthetic c-terminus of the FOS protein in avian species: immunological, physiological and behavioral evidence.

In the past 10 years, the study of the expression of immediate early genes, such as c-fos, in the brain has become a common method for the identification of brain areas involved in the regulation of specific physiological and behavioral functions. The use of this method in avian species has been limited by the paucity of suitable antibodies that cross-react with the FOS protein in birds. We describe in this paper the preparation of an antibody directed against a synthetic fragment of the protein product of the c-fos gene in chickens (Gallus domesticus). We demonstrate that this new antibody can be used in several avian species to study FOS expression induced by a variety of pharmacological, physiological and behavioral stimuli. Western blot studies indicated that this antibody recognizes a protein of the expected size (47 kDa) but also cross reacts to some extent with proteins of lower molecular weight that share sequence homology with FOS (Fos-related antigens). FOS immunocytochemistry was performed with this antibody in four species of birds in three different laboratories utilizing diverse variants of the immunocytochemical procedure. In all cases the antibody provided a reliable identification of the FOS antigen. The new antibody described here appears to be suitable for the study of FOS expression in several different avian species and situations. It is available in substantial amounts and will therefore make it possible to use FOS expression as a tool to map brain activity in birds as has now been done for several years in mammalian species.

Animals↗
PubMed1999

Thyrotropin-releasing hormone concentrations in different regions of the chicken brain and pituitary: an ontogenetic study.

The regional distribution of thyrotropin-releasing hormone (TRH) was studied in the chicken brain. The hypothalamus and the brain stem contained the highest concentration of TRH. Lower amounts were present in the telencephalon, the optic lobes and the cerebellum. Within the hypothalamus, TRH was most abundant in the median eminence. Other important TRH sites were the nucleus paraventricularis magnocellularis, nucleus periventricularis hypothalami, nucleus ventromedialis hypothalami, nucleus dorsomedialis hypothalami and nucleus preopticus periventricularis. On the 14th day of embryonic development (E14), TRH was mostly found in the brain stem. Towards hatching, TRH concentrations increased gradually in both the hypothalamic area and the brain stem. TRH concentrations in the telencephalon, optic lobes and cerebellum remained low. Pituitaries from E14 to E16 chickens were characterized by a high TRH concentration, whereas hypophyseal TRH concentrations dropped towards hatching. Our results support the hypothesis that TRH exerts both endocrine and neurocrine actions in the chicken. On the other hand, high pituitary TRH concentrations were present when hypothalamic concentrations were low and vice versa. Therefore, the chicken pituitary may function as an important source of TRH during early in ovo development at least until the moment hypothalamic control develops.

Animals↗
PubMed1999

Two-year longitudinal study of parotid salivary flow rates in head and neck cancer patients receiving unilateral neck parotid-sparing radiotherapy treatment.

Radiotherapy (RT) is a common treatment for head and neck cancers, and frequently causes permanent salivary dysfunction and xerostomia. This 2-year longitudinal study evaluated unstimulated and stimulated parotid flow rates in 11 patients with head and neck cancers who received unilateral neck parotid-sparing RT. The results demonstrated that treated parotid glands had essentially no output up to 2 years post-RT. Alternatively, spared parotid flow rates were indistinguishable from pre-RT values at 1 and 2 years post-RT, and increased slightly over time. Total unstimulated and stimulated parotid flow rates 2 years after completion of RT were similar to pre-RT values, suggesting that spared parotid function may compensate for lost function from treated parotid glands. These results demonstrate that unilateral neck parotid-sparing techniques are effective in preserving contralateral parotid glands up to 2 years after the completion of RT.

Adult↗
PubMed1999

Effects of timing and duration of feed restriction during rearing on reproductive characteristics in broiler breeder females.

The objective of this study was to determine whether there exists a critical period during rearing when restricted feeding of broiler breeder hens can be most beneficial on subsequent egg production. Broiler breeder pullets were subjected to combinations of either ad libitum or restricted feeding during three periods before sexual maturity. Body weight gain, feed intake, and egg production were recorded. Ovary and oviduct weights were noted at age of first oviposition. At 15 and 18 wk of age and at age of first oviposition, chicken luteinizing hormone releasing hormone-I (cLHRH-I) in the median eminence and the levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in the pituitary and plasma were determined. The results demonstrated that alternation between ad libitum and restricted feeding during rearing changed the growth curves of the birds. Feed restriction from 7 to 15 wk followed by either ad libitum or restricted feeding led to improved reproductive performance, suggesting that long-term feed restriction may not be necessary to attain good reproductive performance. The birds restricted from 7 to 15 wk of age had higher proportional weights of ovary (> or = 1.7%) and oviduct (> or = 1.58%) at age of sexual maturity. The cLHRH-I levels in the median eminence and gonadotrophin contents in the pituitary followed that of growth in response to feeding levels and timing of feeding and could be related to the timing of the onset of lay. At age of first egg, all groups had similar levels of cLHRH-I, LH, and FSH. However, no clear effect of level of feed intake or time period of restriction could be observed for plasma LH or FSH concentrations.

Animal Feed↗
PubMed1998

The effect of food intake from 2 to 24 weeks of age on LHRH-I content in the median eminence and gonadotrophin levels in pituitary and plasma in female broiler breeder chickens.

The present study describes the effect of long-term food restriction on hypothalamopituitary function in the broiler breeder hen during the period prior to sexual maturity. From 1 week of age onward, chickens were divided into 3 groups: one group received food ad libitum (Ad lib); a second group was fed a restricted quantity of food (Res); and a third group was restricted to obtain an intermediate body weight (Int) in between groups one and two. The effects of these feeding regimes on hypothalamopituitary function were assessed by measuring the amounts of cLHRH-I stored in the median eminence (ME) and the pituitary content and plasma levels of gonadotrophins. The Res group had significantly lower levels of cLHRH-I in the ME compared to the Ad lib animals. In all groups, there was a major increase in cLHRH-I in the median eminence about 3 weeks before onset of lay. The age of first oviposition was delayed by 2 and 6 weeks in the Int and Res groups, respectively, compared to the Ad lib animals, indicating that body weight gain patterns are not directly related to the appearance of the first egg. The attainment of sexual maturity may be associated with a threshold value of cLHRH-I stored in the ME in the Ad lib and Int birds. The pituitary LH and FSH contents (after week 16) were positively related to the amount of cLHRH-I in the ME. Plasma FSH concentrations in Ad lib and Int chickens peaked about 3 weeks before the first oviposition and this prepubertal peak was associated with increased pituitary FSH and ME cLHRH-I. There were however no relationships between plasma LH concentrations and pituitary LH content and between plasma LH and cLHRH-I amounts in the ME. The present study demonstrates that the delayed sexual maturation, caused by a chronic food restriction, may be associated with (1) delayed ovarian and oviductal growth, (2) decreased cLHRH-I storage in the ME, and (3) lower levels of LH and FSH in the pituitary. These hormones were however not directly related to levels of food restriction.

Animals↗
PubMed1997

Cognitive impairment in the Amish: a four county survey.

BACKGROUND: The prevalence of probable dementia was determined in a rural, homogeneous community of Amish individuals in the Midwestern USA. The Amish are a genetically isolated group with a low level of formal education (< or = 8 years) and few exposures to modern life, who live in intergenerational setting and have strong social support networks. METHODS: Using community directories, trained interviewers administered the Mini Mental State Examination (MMSE) and a medical history survey to all Amish over 64 years old in a four county area. Individuals with scores < 27 (out of a maximum of 30 points) were given additional neuropsychological tests. Results were reviewed by a neuropsychologist and subjects were classified with regard to probable cognitive impairment. RESULTS: The MMSE scores were inversely related with age and directly with education. The Amish have higher MMSE scores than reported for the general US population. The overall prevalence of probable cognitive impairment for those over 64 years was 6.4%. The prevalence increased with age and lower education and was lowest among married individuals. CONCLUSIONS: The MMSE scores among the Amish were higher than the general population despite their low level of formal education. The lower level of cognitive impairment among the Amish could reflect a lack of inherited susceptibility to dementing diseases, or environmental factors characteristic of their traditional lifestyle. Even among this population with < or = 8 years of formal education, education may protect against cognitive impairment.

Age Distribution↗
PubMed1997

Parotid sparing study in head and neck cancer patients receiving bilateral radiation therapy: one-year results.

Many patients with head and neck cancers receive radiation therapy as part of their treatment which frequently causes considerable morbidity, including various degrees of permanent salivary gland dysfunction. Three-dimensional treatment planning [3-DTP] and conformational dose delivery constitute a new therapeutic modality that conforms the high-dose radiation volume to the shape of the tumor volume while minimizing the dose to tissue that is not at risk of containing cancer. The treatment volumes for head and neck tumors as well as parotid glands can be well-defined on cross-sectional CT imaging techniques. The purpose of this investigation is to determine if 3-DTP and conformational dose-delivery could minimize radiation dose and salivary gland dysfunction to contralateral parotid glands in patients with head and neck cancers. Eleven patients with head and neck cancers who required bilateral radiation therapy were treated with 3-DTP. Unstimulated and stimulated bilateral parotid saliva was collected prior to radiotherapy, weekly during treatment, and 1, 3, 6, and 12 months after the completion of radiotherapy. Treated parotid glands received an average dose of 5745 cGy, while spared glands received only 1986 cGy (p < 0.0001). Unstimulated and stimulated parotid flow rates decreased dramatically in treated glands after the initiation of radiotherapy, remained at extremely low rates without any improvements, and were significantly lower at 1 year after radiotherapy compared with baseline. Conversely, parotid flow rates in spared glands underwent mild changes during radiotherapy and were approximately 50% of baseline values. The results of this study suggest that with the use of 3-DTP, contralateral parotid gland function can be partially preserved for at least 1 year in patients with head and neck cancers requiring bilateral radiation.

Aged↗
PubMed1996

Ipsilateral parotid sparing study in head and neck cancer patients who receive radiation therapy: results after 1 year.

OBJECTIVE: To determine if three-dimensional treatment planning and conformational dose delivery could minimize radiation dose and salivary gland dysfunction to contralateral parotid glands in patients with unilateral head and neck cancers. STUDY DESIGN: Fifteen patients with unilateral head and neck cancers were treated with three-dimensional treatment planning. Unstimulated and stimulated bilateral parotid saliva was collected before radiotherapy, weekly during treatment, and 1, 3, 6, and 12 months after the completion of radiotherapy. RESULTS: Treated parotid glands received an average dose of 4949 cGy, whereas spared glands received only 355 cGy. Unstimulated and stimulated parotid flow rates decreased dramatically in treated glands after the initiation of radiotherapy and were significantly lower at 1 year after radiotherapy compared with baseline. Conversely, parotid flow rates in spared glands underwent mild changes during radiotherapy and were similar at 1 year after radiotherapy compared with baseline. CONCLUSION: Parotid gland function can be preserved for at least 1 year in patients with unilateral head and neck cancers with three-dimensional treatment planning.

Adult↗
PubMed1995

Noradrenergic system in the chicken brain: immunocytochemical study with antibodies to noradrenaline and dopamine-beta-hydroxylase.

A light microscopic immunocytochemical study, using antisera against noradrenaline (NA) and dopamine-beta-hydroxylase (DBH), revealed the noradrenergic system in the brain of the chicken (Gallus domesticus). NA- and DBH-immunoreactive (ir) elements showed a similar distribution throughout the whole brain. The neurons immunoreactive for the monoamine were confined to the lower brainstem, the pons, and the medulla. In the pons, a rather dense group of cells was found in the dorsal, most posterior part of the locus coeruleus and in the caudal nucleus subcoeruleus ventralis. A few labeled cells appeared in and around the nucleus olivaris superior in the most caudal part of the metencephalic tegmentum. In the medulla oblongata, noradrenergic cells could be visualized at the level of the nucleus of the solitary tract and in a ventrolateral complex. Virtually all regions of the brain contained a rather dense innervation by NA- and DBH-immunopositive varicose fibers. Noradrenergic fibers and terminals were especially abundant in the ventral forebrain and in the periventricular hypothalamic regions. DBH-ir and NA-ir fibers, varicosities, and punctate structures could be observed in close association with immunonegative perikarya in several brain regions, more specifically in the ventral telencephalon, in the mid- and tuberal hypothalamic region, and in the dorsal rostral pons. Some perikarya in these brain areas were completely surrounded by noradrenergic structures that formed pericellular arrangements around the cells. The present study on the distribution of the noradrenergic system in the brain of the chicken combined with the results of a previous report on the distribution of L-Dopa and dopamine in the same species (L. Moons, J. van Gils, E. Ghijsels, and F. Vandesande, 1994, J. Comp. Neurol. 346:97-118) offers the opportunity to differentiate between the various catecholamines in the brain of this vertebrate. The results are discussed in relation to catecholaminergic systems previously reported in avian species and in the mammalian brain.

Adrenergic Fibers↗
PubMed1995

Efficacy of an inactivated hepatitis A vaccine in pre- and postexposure conditions in marmosets.

A two-part challenge study was done in marmoset monkeys to confirm the efficacy of an inactivated hepatitis A vaccine. In part 1 (preexposure), 7 marmosets received a single low dose of vaccine (360 ELISA units [EL.U.]) and were challenged orally with wild type hepatitis A virus (HAV) either 1 or 6 months later. In part 2 (postexposure), 8 marmosets were challenged orally with HAV and then half each were inoculated with a single dose of 360 or 1440 EL.U. of vaccine 2 days later. The suboptimal immune response elicited by the low vaccine dose in the preexposure group was sufficient to induce complete protection against oral challenge with heterologous HAV in all marmosets that had responded serologically. In the postexposure group, the 360-EL.U. dose of vaccine resulted in partial protection against hepatitis A disease, whereas the 1440-EL.U. dose of vaccine elicited complete protection against disease and virus excretion.

Animals↗
PubMed1994

Clinical and immunological investigation of a new combined hepatitis A and hepatitis B vaccine.

As with hepatitis B vaccines, the recently developed hepatitis A vaccine is suitable not only for individual protection, but also for public health control measures. For introduction into routine immunisation programmes, however, hepatitis A vaccine should preferably be combined with other already established vaccines. In particular, a combination of hepatitis A and hepatitis B vaccines would be appropriate. We investigated a new combined hepatitis A/hepatitis B vaccine comparing its tolerability and immunogenicity with that obtained after separate or mixed simultaneous administration of the two components. Three groups of healthy volunteers, each of approximately 50 persons, were included. All were negative for hepatitis A and hepatitis B markers and had normal liver enzyme values. They received hepatitis A (720 ELISA units) and hepatitis B (20 micrograms) vaccines in the deltoid muscle, combined, mixed or separately, according to a 0, 1, 6-month schedule. Blood samples for determination of antibodies to hepatitis A virus (anti-HAV) and hepatitis B virus (anti-HBs) and of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were drawn at months 0, 1, 2, 6, and 7. Local and systemic reactions were monitored by means of questionnaires. The results of our study demonstrate that the combined hepatitis A and B vaccine is well tolerated and highly immunogenic. The seropositivity and seroprotection rates were 100% for both antigens in all groups. Surprisingly, anti-HAV and anti-HBs antibody titres after the combined and mixed vaccines were significantly higher compared with the respective monovalent vaccines injected separately.

Adult↗