Biomedical subjects

R Buijs

Publications and source records attributed to R Buijs.

9 recordsLinked to original sources

PubMed2001

Parish nurses influencing determinants of health.

How are the concepts health, health promotion, faith community, and health determinants connected? How can a nurse draw on the unique features of a faith community to promote health? In this article, we explore the relations among these concepts and consider the answers to these questions. Parish nurses provide a concrete example of the interactions among these concepts. They are often hired by faith communities to intentionally promote health within and beyond the faith community. Increasingly, faith communities are being used as settings for health promotion interventions. We describe examples of how a parish nurse can influence 2 determinants of health: social support and healthy child development.

Adult↗

PubMed1999

Mammalian Cry1 and Cry2 are essential for maintenance of circadian rhythms.

Many biochemical, physiological and behavioural processes show circadian rhythms which are generated by an internal time-keeping mechanism referred to as the biological clock. According to rapidly developing models, the core oscillator driving this clock is composed of an autoregulatory transcription-(post) translation-based feedback loop involving a set of 'dock' genes. Molecular clocks do not oscillate with an exact 24-hour rhythmicity but are entrained to solar day/night rhythms by light. The mammalian proteins Cryl and Cry2, which are members of the family of plant blue-light receptors (cryptochromes) and photolyases, have been proposed as candidate light receptors for photoentrainment of the biological clock. Here we show that mice lacking the Cryl or Cry2 protein display accelerated and delayed free-running periodicity of locomotor activity, respectively. Strikingly, in the absence of both proteins, an instantaneous and complete loss of free-running rhythmicity is observed. This suggests that, in addition to a possible photoreceptor and antagonistic clock-adjusting function, both proteins are essential for the maintenance of circadian rhythmicity.

Animals↗

PubMed1996

Subgrouping of bovine respiratory syncytial virus strains detected in lung tissue.

Bovine respiratory syncytial virus is an important respiratory pathogen in cattle. Recently, subgroups of BRSV have been identified, based on antigenic differences. However, little is known about subgroups of BRSV that circulate in the cattle population. Therefore, we determined the reactivity of monoclonal antibodies (mAbs), directed against the G, F, or P protein of BRSV, with lung tissue from 47 calves, that suffered from severe respiratory disease. Fourteen animals (30%) proved to be infected with BRSV, because they all reacted with mAbs against the P or F protein, as detected by fluorescent antibody tests. Monoclonal antibodies against the G protein were able to discriminate between the BRSV-positive specimens: 7 strains were identified as subgroup A strains, and 5 strains as subgroup AB, which is introduced as BRSV subgroup in this paper. Two strains could not be identified unambiguously. It is concluded that BRSV subgroup A and AB were associated with severe respiratory disease, and that strains belonging to either subgroup circulated concurrently in the cattle population in the Netherlands.

Animals↗

PubMed1994

The vasopressinergic innervation of the lateral septum of the rat after chronic alcohol consumption and withdrawal.

We have recently reported that ethanol ingestion induces morphological changes in the vasopressinergic neurons of the supraoptic nucleus and that withdrawal from alcohol partially reverses these alterations. Since the production of vasopressin is not restricted to the magnocellular neurons of the hypothalamus, we investigated the effects of long-term ethanol intake and withdrawal on the lateral septum, an area heavily innervated by vasopressinergic fibers. Besides, as ethanol leads to a decrease of the plasma levels of testosterone, a hormone which plays a pivotal role in the development and maintenance of the vasopressinergic innervation of the lateral septum, we included groups of alcohol-fed animals submitted to testosterone replacement both in physiological and supraphysiological doses. In ethanol-treated rats there was a marked reduction in the number of vasopressin-immunoreactive fibers in the lateral septum. Following ethanol withdrawal a partial recovery in the number of vasopressin-immunoreactive fibers was observed. In both groups of ethanol + testosterone-treated animals the vasopressinergic innervation was increased when compared to the alcohol-fed group, although a complete reversal was not achieved. Therefore, two mechanisms might be regarded as underlying the impoverishment of the vasopressinergic innervation in the lateral septum after prolonged alcohol consumption: alcohol-induced cell death in the bed nucleus of the stria terminalis, from where these fibers arise, and/or alcohol-induced decrease in testosterone plasma levels.

Animals↗

PubMed1991

Glutamate-like immunoreactivity in retinal terminals in the nucleus of the optic tract in rabbits.

The ultrastructural organization of retinal terminals within the nucleus of the optic tract of rabbits was investigated with a combination of anterograde tracing and immunocytochemistry. The anterogradely transported WGA-HRP injected in the vitreous of the eye was visualized with the sensitive gold-substituted silver peroxidase (GSSP) method. Glutamate and GABA immunoreactivity were identified with postembedding colloidal gold particles. Retinal ganglion cell terminals (R-terminals) in the nucleus of the optic tract formed asymmetric synapses and contained spherical vesicles and electron lucent mitochondria. R-terminals were observed in large clusters in the neuropil and in synaptic contact with large initial dendrites and somata. Within the clusters of neuropil the R-terminals formed two types of glomeruluslike arrangements: (1) an R-terminal centrally located and surrounded by small dendritic and axonal profiles and (2) several R-terminals surrounding a single dendrite or a group of dendritic profiles, presumably of interneuronal origin. All R-terminals identified with WGA-HRP as well as those exhibiting similar ultrastructural characteristics showed high levels of glutamate immunoreactivity, but no GABA immunoreactivity. The presence of glutamate and the absence of GABA in R-terminals suggest that glutamate is involved in neurotransmission in the pathway from retina to the nucleus of the optic tract of rabbits.

Animals↗

PubMed1988

Cardiovascular input to hypothalamic neurosecretory neurons.

In vivo extracellular recordings from rat supraoptic and paraventricular magnocellular neurosecretory cells (MNCs) indicate that putative vasopressin-secreting MNCs may be identified by an abrupt and brief cessation in firing consequent to a transient drug-induced rise in arterial pressure sufficient to activate arterial baroreceptors. In the diagonal band of Broca (DBB), a population of neurons projecting towards the supraoptic nucleus are activated during this drug-induced hypertension. Electrical stimulation in DBB selectively depresses supraoptic vasopressin-secreting MNCs. Intracellular recordings in perfused hypothalamic explants confirm a DBB-evoked bicuculline-sensitive and chloride-dependent postsynaptic inhibition, similar to that associated with the application of gamma-aminobutyric acid (GABA) in approximately half of supraoptic MNCs. Since bicuculline also selectively blocks baroreceptor-induced inhibition in supraoptic MNCs, it is proposed that the depressant baroreflex input to vasopressin-secreting MNCs involves a population of DBB neurons and GABAergic interneurons located close to MNCs. An excitatory and selective input to vasopressin-secreting MNCs follows chemoreceptor activation, possibly mediated by the A1 noradrenergic cell group in the ventrolateral medulla. Another excitatory input to both vasopressin- and oxytocin-secreting MNCs is triggered by circulating angiotensin II and appears to be relayed centrally through an angiotensinergic projection from the subfornical organ.

Action Potentials↗

PubMed1987

Monoaminergic fibers form conventional synapses in the cerebral cortex.

The morphological characteristics of the monoaminergic axon-terminals in the mammalian cerebral cortex have been the subject of controversy in recent years. Systematic analysis of serial ultrathin sections, immunocytochemically stained with antibodies against noradrenaline and serotonin, has shown that nearly all stained terminals form synapses characterized by specialized junctional appositions. These results suggest that, contrary to the widely held view, monoamines in the cortex are released at specialized junctions.

Animals↗

PubMed1984

Byrne and Long: a classification for rating the interview style of doctors.

In order to assess the doctor's verbal behaviour in the consultation, a classification instrument is needed that will enable us to summarize the doctor's interview style. Such an instrument, developed by Byrne and Long, is evaluated in this study. After presenting the procedure as it has been worked out by Byrne and Long, some points of criticism are formulated. On account of our criticism, some changes have been introduced into the instrument. To test the relevance and reliability of the instrument, 36 consultations have been classified according to the adjusted system. This procedure showed that it was possible to represent a consultation with the 45 categories the system consisted of (although only 15 categories occurred in more than half of the consultations). Those categories that occurred often enough, could be measured with sufficient reliability, with inter-observer reliability coefficients mostly above 0.70. An example shows that the procedure is extremely useful to indicate certain differences between doctors and types of consultations.

Disease↗

PubMed1983

An improved method for embedding hard tissue in polymethyl methacrylate.

An improved routine method for embedding tissue, especially hard tissue, in polymethyl methacrylate (pMMA) is described. The improvements were: the final dehydration step before MMA infiltration was performed with methanol in a Soxhlet apparatus; the stabilizer hydroquinone was not extracted from the monomer (MMA), and more important, the commonly used polymerization initiator, benzoyl peroxide (bpo), was replaced by the initiator, bis (4-tert-butylcyclohexyl)peroxydicarbonate (bbpd). Bbpd is preferred to bpo because it is not explosive, far less is needed and it has a suitable half life. Moreover, bbpd, as obtained from the manufacturer, needs no further purification, in contrast to bpo. Temperatures during bbpd initiated polymerization did not exceed 48 C. In bbpd initiated pMMA, bubbles were almost never generated.

Benzoyl Peroxide↗