T-cell ratios in New York City prostitutes.
Explore the source record for details and available documents.
Adult↗
Biomedical subjects
D Jordan
Publications and source records attributed to D Jordan.
Circannual variations of TSH circadian rhythm parameters in the rat.
We had previously observed a circadian rhythm for serum TSH in male Sprague-Dawley rats (under a 12-hour light-dark cycle, light off at 19.00 h). In the present work the parameters of this previously observed TSH rhythm were determined over a year on a monthly basis. A circadian rhythm was detected for each month except April. From month to month, the amplitudes and acrophases of these rhythms were not significantly different, and a circannual rhythm was only established for the mean TSH concentration over the 24-hour period (mean hormonal value). We conclude that there is a constant circadian pattern for serum TSH fluctuations superimposed on a small basal circannual rhythm of the mean hormonal value.
Animals↗
[Topographic and chemical study of the GABA synthetizing enzyme in Parkinsonian syndromes].
After a classical neuropathological study assessing the diagnosis, the activity of the GABA synthetizing enzyme, glutamate decarboxylase (GAD), was assayed in 6 brain areas, in 8 cases of Parkinson's disease, 2 cases of idiopathic orthostatic hypotension and 9 control cases carefully matched. The activity of GAD is not impaired, as classically believed, in parkinsonian brains, particularly in substantia nigra and pallidum. This preservation would indicate the absence of lesion of GABAergic neurones in Parkinson's disease. In the cases of other Parkinsonian syndromes, the number of cases studied is too limited to allow any generality; but they are, however reported because of their rarity.
Aged↗
The location and properties of preganglionic vagal cardiomotor neurones in the rabbit.
The origins of preganglionic vagal neurons which slow the heart in the rabbit have been examined with standard neurophysiological stimulation and recording techniques. The activity of 216 neurones projecting to the right cervical vagus nerve have been recorded in localized areas of the brain stem. Thirty-six of these neurones were classified as cardiomotor neurones since they had properties similar to those described for such neurones in the cat. All had efferent axons in the range of B fibres. They could be synaptically activated by electrical stimulation of the ipsilateral aortic nerve which in the rabbit is solely barosensory. The majority of these neurones (70%) were spontaneously active and those which were normally silent could be made to fire by iontophoretic application of DL-homocysteic acid (an excitant amino acid). This spontaneous, or evoked, activity showed evidence of a pulse rhythm (of baroreceptor origin) and respiratory modulation (firing predominantly during expiration). In response to application of DL-homocysteic acid, the neuronal excitation was usually accompanied by a small but significant bradycardia. Histological examination showed that these neurones were located in both the dorsal vagal nucleus and the nucleus ambiguus.
Animals↗
Case report 187. Congenital intraosseous arteriovenous macrofistulous anomaly (malformation).
Explore the source record for details and available documents.
Adolescent↗
Identification and brain-stem projections of aortic baroreceptor afferent neurones in nodose ganglia of cats and rabbits.
1. The retrograde transport of horseradish peroxidase (HRP) was used to locate cell bodies of afferent neurones with axons in the aortic nerves within the nodose ganglia of cats and rabbits. 2. In the rabbit HRP-labelled cells were localized to the medial aspect of the ganglion in the vicinity of the entry of the superior laryngeal and aortic nerves. 3. A similar grouping of labelled cells in rostro-medial aspects of the ganglion was seen in the cat, though there were many other labelled cells distributed throughout the ganglion. It is suggested that the former cells may be barosensory and the latter chemosensory. 4. Extracellular recordings were made from baroreceptor afferents in the nodose ganglia of rabbits and cats using glass micro-electrodes. Recordings sites were confined to rostral regions of the ganglia. 5. The projections of single baroreceptor afferents were studied by antidromic activation from the medulla oblongata using electrical stimulation applied through tungsten--glass micro-electrodes. Evidence is presented on the basis of depth--threshold contours and antidromic latency which indicates that stimulation of the main axons can be distinguished from stimulation in areas of branching and presumed termination. 6. In cats aortic baroreceptor afferents gave branches to either medial (three out of six) or lateral (three out of six) subnuclei of the nucleus tractus solitarius (n.t.s.). One neurone had additional projections to the contralateral medial subnuclei of the n.t.s. 7. In rabbits the afferents have branches mainly to lateral subnuclei of the n.t.s. (seven out of eight neurones) with only one giving branches to the medial subnucleus of the n.t.s. and additionally to the nucleus alaris. 8. Projections to the medulla extending beyond the immediate vicinity of the n.t.s. were found in either species.
Action Potentials↗
The brain-stem projections of pulmonary stretch afferent neurones in cats and rabbits.
1. Micro-electrode recordings were made from slowly adapting pulmonary stretch afferents within the nodose ganglia of cats and rabbits. Recordings sites were distributed throughout the ganglia. 2. The projections of these afferents to the medulla oblongata were studied by antidromic stimulation. 'Point' and 'Field' type depth--threshold curves were interpreted as corresponding to stimulation of the main afferent axons and its branches, respectively. Increases in antidromic latency in conjunction with 'field' contours was additional evidence in support of this interpretation. 3. In cats, most (six out of seven) afferents had extensive branches, and probably also terminations, within the medial subnucleus of the ipsilateral nucleus tractus solitarius (n.t.s.). Two of these, plus one other afferent, also had projections to the lateral and ventrolateral subnuclei. 4. In rabbits the projections of such afferents were similar, i.e. mainly to the medial subnucleus of the n.t.s. (eight out of eleven) but also extending into the nucleus alaris, and occasionally to lateral and ventrolateral subnuclei (two out of eleven) or to both regions (one out of eleven). 5. Branching of single afferents was seen to occur over up to 3 mm of the rostro-caudal extent of the intermediate region of the n.t.s. The significance of the observations is discussed.
Action Potentials↗
Effects of starvation on circadian variations of plasma TSH in rats.
Diurnal fluctuations of plasma TSH were investigated in ad libitum fed rats as well as after a 3 day starvation period in order to study the relationship between the circadian pattern of TSH secretion and nutritional status. Our study showed the persistence of a circadian TSH rhythm after a 3-day starvation without any change in the amplitude of plasma TSH variations. However, the 24 h average plasma TSH levels were significantly lower. A suggestive acrophase occurred at the same period of the day in starved and fed rats. Our results suggest that the control of plasma TSH concentrations and nycthemeral rhythm are not closely related and may even possibly be independent of one another.
Animals↗
Respiratory modulation of afferent terminal excitability in the nucleus tractus solitarius.
The excitability of vagal and carotid sinus nerve afferent terminals within the nucleus of the tractus solitarius has been studied in cats and rabbits using the technique of antidromic activation. Although the excitability of superior laryngeal nerve afferent terminals was observed to fluctuate in phase with the central respiratory cycle, no equivalent variations in sinus nerve terminal excitability were observed. Whilst recording from single identified vagal afferents, no respiratory-related changes in the excitability of baroreceptor afferent terminals could be demonstrated, though such modifications in terminal excitability were readily seen in lung stretch afferent terminals.
Afferent Pathways↗
Effects of acetylcholine on respiratory neurones in the nucleus ambiguus-retroambigualis complex of the cat.
1. The effects of ionophoretic application of acetylcholine (ACh) and cholinergic antagonists to respiratory neurones of the nucleus ambiguus-retroambigualis complex were studied in cats. 2. Acetylcholine was ineffective when applied to inspiratory neurones (27/31) but inhibited the spontaneous activity of a significant population of expiratory neurones (21/39). 3. The expiratory neurones inhibited by ACh included neurones with axons projecting to the vagus or spinal cord, as well as neurones not antidromically activated from either of these sites. 4. The cholinergic inhibition of expiratory neurones was blocked by atropine (6/9) but dihydro-beta-erythroidine was ineffective. In seven expiratory neurones, ionophoresis of atropine alone evoked firing during the normal period of silence of the neurone (inspiration). 5. It is concluded that a significant population of expiratory neurones receive an active inhibition during inspiration and this involves a cholinergic mechanism. The implications of these observations for the synaptology of central respiratory control and modifications of the vagal outflow to the heart are discussed.
Acetylcholine↗
Metabolism of adiphenine. I. Absorption, distribution and excretion in rats and mice.
1. The disposition of adiphenine labelled with 14C in two positions has been investigated in rats and mice after i.v. administration, and has been compared with that of the [14C]diethylethanolamine HCl and of the [14C]diphenylacetic acid. 2. Radioactivity in the blood declined in a biphasic manner. Biliary elimination depended upon the 14C-labelled compound administered: less than 5% dose for the diethylethanolamine moiety, 100% dose for the carboxylic moiety. Of the radioactivity appearing in rat bile, less than 1% is associated with unchanged adiphenine. 3. In preliminary metabolic studies, three major metabolites have been identified: diphenylacetic acid, diethylethanolamine and a diphenylacetic acid glucuronide. 4. Uptake by the brain of [14C]adiphenine shortly after dosing is 15 times greater than that of blood. Radioactivity is also found in the hypophysis, the adrenals and melanoid pigments, with a concn. up to 30 times greater than that found in the blood.
Absorption↗
Evidence for circadian variations in serum thyrotropin, 3,5,3'-triiodothyronine, and thyroxine in the rat.
We previously observed that under a 12-h light, 12-h dark schedule (lights off at 1900 h), male Sprague-Dawley rats showed a circadian rhythm for serum TSH with a zenith near midday. In the present work we further characterized the serum TSH rhythm by appropriate mathematical analysis. The peak of serum TSH occurred at 1130 +/- 0105 h (mean of five experiments), with an amplitude of 0.2 +/- 0.1 microgram/ml, while the TSH level was minimum at the beginning of the dark period; the period of the TSH rhythm was 24.5 +/- 0.6 h. A circadian rhythm was also demonstrated for serum T3 and T4; these rhythms were characterized by peaks occurring 1.5 and 2.2 h after that of TSH, respectively. As expected, characteristics of the rhythm were more narrowly defined for T3 than for T4. Serum concentrations peaked at 1256 +/- 0206 and 1346 +/- 0308 h for T3 and T4, respectively; the serum T3 concentration varied from 78.7 +/- 7.8 to 54.2 +/- 2.7 ng/100 ml (P < 0.001) and serum T4 varied from 7.3 +/- 1.1 to 5.1 +/- 0.5 microgram/100 ml (P < 0.05) for zenith and nadir values, respectively. It is suggested that the diurnal peaks of thyroid hormones might be related to TSH-induced changes in thyroid secretion.
Animals↗
The role of pharmaceutical services in cost containment.
Explore the source record for details and available documents.
Cost Control↗
Serotonin and endocrine rhythms.
The biological rhythms belong partly to the genetic patrimony and partly to the environmental patterns. The main results have been obtained on the hormonal fluctuations which are mostly controlled by the hypothalamopituitary system. Thus they include modulations of neurotransmitters activity especially serotonin. Experimental facts have been gathered in different species for ACTH, growth hormone, prolactin TSH and gonadotropins rhythms. These phenomenona are integrated in a general organization which includes sleep-waking cycle.
Adrenocorticotropic Hormone↗
[Studies of the effect of 2,3-dioxoindolin (isatin) in comparison with serotonin on the isolated guinea pig ileum].
In preparations of the isolated guinea-pig ileum 2,3-dioxoindoline shows a dose-dependent stimulating activity. In a contraction range between 5 x 10(-5) to 2 x 10(-3) moles/l this compound is spasmogenic and causes concentration (pD2 = 3.3). Prolonged contact time of higher concentrations of isatin results in a reduction of excitation and a relaxation of the ileum. An additive synergism is seen in combined treatment with serotonin. Pretreatment with serotonin antagonists reduces the stimulating effect of isatin. Quantitative differences in inhibition by dihydroergotamine and benzyloxygramine in contrast to morphine or atropine actions provided evidence that the stimulating activity of isatin is mainly mediated through the "D" receptors on the smooth muscle cells. Besides its stimulating effect isatin also exhibits blocking activity when tested against 5-HT (ACh). In high concentration (> 2 mmoles/l) isatin is able to antagonize--after only 2 min of pre-incubation--responses to 5-HT completely. In this range dose-response curves become progressively flatter and their maxima decline in a non-competitive way.
Animals↗
Studies on the excitability of sinus nerve afferent terminals.
1. The excitability of sinus nerve afferent terminals within the nucleus of the tractus solitarius has been studied in cats and rabbits using the technique of antidromic activation. 2. Conditioning stimuli to the hypothalamic defence area increased the excitability of some glossopharyngeal nerve afferents, though no such effects were observed on sinus nerve terminals. 3. Although the excitability of superior laryngeal nerve afferent terminals was observed to fluctuate in phase with the central respiratory cycle, no equivalent variation in sinus nerve terminal excitability were observed. 4. It is concluded that sinus nerve afferent terminals are not influenced by presynaptic mechanisms. Possible sites for the observed modulations of baroreceptor and chemoreceptor reflexes are discussed in the light of these results.
Animals↗
Evaluating the endurance athlete's heart: a non-invasive graphic study.
Explore the source record for details and available documents.
Adult↗
Participation of serotonin in thyrotropin release. II. Evidence for the action of serotonin on the phasic release of thyrotropin.
During a 12-h light 12-h dark schedule (lights off at 1900 h), male Sprague-Dawley rats show a circadian rhythm of plasma TSH with a zenith near midday. The participation of serotonin (5HT) in the phasic release of TSH was studied using both pharmacological and surgical-stereotaxical approaches. Animals treated with parachlorophenylalanine methyl ester (pCPA), an inhibitor of 5HT synthesis (one or two injections of 250 mg/kg each) showed a reduction or a disappearance of the diurnal peak of TSH, respectively. Additional treatment by 5-hydroxytryptophan, a precursor of 5HT, completely, restored the diurnal TSH peak. Treatment with 5,6-dihydroxytryptamine creatine sulfate, a neurotoxin which selectively destroys 5HT terminals, also induced alterations of the diurnal peak of TSH. There were no major modifications observed in the low nocturnal levels of TSH in rats treated with pCPA, 5-hydroxytryptophan, or 5,6-dihydroxytryptamine. The major serotoninergic innervation of the hypothalamus originates from the raphe dorsalis or centralis; destruction of these two nuclei caused a quasiabolition of the diurnal TSH peak (only a low amplitude TSH circadian rhythm persisted). Hypothalamic 5HT content was measured in the majority of these experiments; the greatest depletions (near 90%) were observed after two injections of pCPA or in rats bearing raphe lesions. We conclude that the diurnal peak of TSH, observed during the physiological circadian rhythm, is serotoninergic dependent.
5,6-Dihydroxytryptamine↗