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The effect of cervical vagotomy (decentralization) on the ultrastructure of the carotid body on the duck, Anas platyrhynchos.

Carotid bodies of ducks show no detectable changes in ultrastructure up to periods of four weeks following the removal of 2-3 cm of the cervical vagus (decentralization). This indicates that the majority, and possibily all the nerves terminating on the glomus cells are afferent (sensory) in nature. These nerve endings are in reciprocal synaptic contact with the glomus cells and therefore have efferent and afferent functions. Theories concerning the carotid body receptor mechanism are discussed with particular reference to those theories which ascribe functions to the reciprocal synapses.

Animals↗

Control of ACh sensitivity in temporarily unconnected ("decentralized") segments of diaphragm-muscle fibres of the rat.

1. After a local lesion of the diaphragm muscle, which produced a segment of innervated muscle fibres connected with an intact nerve-free segment by a region of crushed muscle fibres, the sensitivity to ACh, the presence of tetrodotoxin resistant action potentials (AP) and the transmission of AP along the muscle fibres were studied. 2. Three days after local injury of the diaphragm muscle ACh sensitivity and TTX resistance appeared in the crushed and nerve-free segments between the place of injury and the tendineous attachment. 5-7 days after injury transmission of action potentials through the damaged to the undamaged ("decentralized"), nerve-free part of the fibres is restored. High ACh sensitivity and TTX resistance of the latter segment, however, are completely lost only 20 days after the local injury. During this period contractility of the muscle remains practically unchanged. Enzymatic activities (SDH, ATPase and phosphorylase) of the damaged part were lost 3 days after crushing and recovered slowly between 7-10 days of regeneration of the diaphragm muscle fibres. 3. The experiments suggest that during regeneration of damaged muscle fibres supersensitivity to ACh remains high inspite of normal AP activity and that intracellular mechanisms may be involved in the induction and disappearance of ACh hypersensitivity.

Acetylcholine↗

Effects of deneravation and decentralization upon taste buds.

Denervation of vallate papillae results in failure of tactile and gustatory reception at a time when impulse conduction in the distal stump of the glossopharyngeal nerve is still unimpaired; delay of receptor deficit depends on axon length between receptor and axotomy sites; taste buds disappear by 10 days. Decentralization, through intracranial rhizotomy, does not modify lingual receptors structure or function.

Animals↗

[Decentralization--a social psychiatric key idea: experiences at the St. Gallen Canton].

In the St. Gallen county community care was not only organised in a decentralized way but also was anchored regionally by political means. Regional societies and community politicians are responsible for organizing and funding community care. After 17 years of experience, some of the consequences of this direct political influence on community care are reported.

Community Mental Health Services↗

Decentralized impulsive control for a class of uncertain interconnected systems.

A great deal of stabilization criteria has been obtained from study of stabilizing interconnected systems. The results obtained are usually based on continuous systems by state feedback. In this paper, decentralized impulsive control is presented to stabilize a class of uncertain interconnected systems based on Lyapunov theory. The system under consideration involves parameter uncertainties and unknown nonlinear interactions among subsystems. Some new criteria of stabilization under impulsive control are established. Two numerical examples are offered to prove the effectiveness and practicality of the proposed method.

Computer Simulation↗

Amylase in parotid saliva of rats after sympathetic nervous decentralization.

The marked increase in the amylase secretion that occurs in parasympathetic saliva some days after sympathetic ganglionectomy occurred after decentralization also; hence, it results from lack of impulses from the central nervous system. It occurred whether salivation was evoked by activating muscarinic receptors with methacholine, peptidergic receptors with substance P or physalaemin, or alpha-adrenoceptors with phenylephrine. Unilateral operation affected to some degree the contralateral gland also.

Amylases↗

Decentralization of the superior cervical ganglion in neonates impairs the development of the innervation of the iris. A quantitative ultrastructural study.

The superior cervical sympathetic ganglion was decentralized unilaterally by section of the preganglionic chain in 2- or 4-day-old rats. Twenty-one days post-operatively the dilator muscle of the iris was examined electron microscopically. Quantitative estimates demonstrated that there was a reduction both in the numbers of axon bundles and of individual axons in the iris innervated by the deafferented ganglion as compared with its fellow of the contralateral control side.

Animals↗

Effect of decentralization and glucose withdrawal on the potassium-induced cAMP increase in the rabbit superior cervical ganglion.

The concentration of cAMP in the isolated rabbit superior cervical ganglion (SCG) increases when the tissue is exposed to high potassium media for short periods. The increase was found not to be affected by agents that are known to potentiate or to antagonize the postsynaptic effects of acetylcholine. Pretreatment of the rabbits with various sympaticolytic substances did not appear to affect the cAMP increase in the isolated SCG. It was found that the K+-induced cAMP synthesis occurred neither in ganglia which had been decentralized 3 days before isolation nor in intact ganglia preincubated in a glucose-free medium. Under both these conditions the effect of potassium declines with a time course which is characteristic for the degeneration of the presynaptic terminals. These terminals therefore, appear to be the most likely site for the cAMP increase.

Animals↗

Beyond decentralization: the evolution of population distribution in England and Wales, 1961-1981.

"Using preliminary figures from the 1981 Census, this paper details recent population shifts at a variety of areal scales in England and Wales. It compares trends in the 1971-1981 period with those in the previous decade and assesses the relative contributions of net migration and natural change. Within its broad descriptive objectives, the paper considers whether England and Wales has kept abreast of patterns of counter-urbanization that have been claimed for other industrialized nations." The authors propose some definitions for various terms, including decentralization, deconcentration, and counter-urbanization. "The conclusion is drawn that even if the postulated international continuum of changes ranging from urbanization through to counter-urbanization is valid, the limited geographical size of England and Wales will preclude this country from reaching the final stages of such a model. Finally, some policy implications which stem from the recent population redistributions are introduced and some themes for future research are considered."

Demography↗

Increase in protein kinase-C-beta-like immunoreactivity (PKC-beta-LI) in the rat superior cervical ganglion after decentralization.

The effect of decentralization on protein kinase-C-beta-like immunoreactivity (PKC-beta-LI) in the rat superior cervical ganglion (SCG) was studied. The cervical sympathetic trunk was transected and at different time points (0 h-14 d) after transection the rats were decapitated and the SCGs examined immunohistochemically. In the control ganglia only faint PKC-beta-LI was seen in the principal neurons, whereas several strongly immunolabelled nerve fibers were observed. In the principal ganglionic neurons PKC-beta-LI was found to be increased 1-8 days after denervation, with the maximum accumulation occurring at 4 days. Fourteen days post-transection PKC-beta-LI in the neuronal perikarya was back to the initial level, but a decrease in the number of PKC-beta-immunoreactive nerve fibers was observed. The results suggest that the amount of PKC-beta in the principal neurons of the rat SCG may be partly regulated transsynaptically by preganglionic innervation.

Animals↗

Persistent firing of splenic and renal nerves after acute decentralization but failure to produce ganglionic reflexes.

Experiments were done to evaluate the contribution of peripheral neural circuits to generation of ongoing splenic and renal sympathetic discharge as well as to the reflex alteration of this discharge by chemical stimulation of receptors of intestinal afferent nerves. After decentralization of the celiac and superior mesenteric ganglia, low amplitude spikes with low discharge rates still were observed in both nerves. Stimulation of intestinal receptors with bradykinin or capsaicin did not alter this residual firing. Cholinergic blockade eliminated most of this discharge. The source of the residual firing and its contribution to basal discharge of splenic and renal nerves remains to be determined.

Action Potentials↗

Long-term survival of decentralized axons and incorporation of satellite cells in motor neurons of rock lobsters.

Previous electrophysiological experiments have shown that in the abdominal extensor muscles of rock lobsters, axons which were cut in surviving animals do not degenerate peripherally for several months, but conduct action potentials and release transmitter quanta on stimulation closely distal to the scar. Electron micrographs from the axon distal to the scar (in a reliably conducting region) show invasion of the axoplasmic space by nucleated cells, probably glia. After several months, the cell membranes of the invaders have vanished and apparently functional multiple nuclei remain. We suggest that decentralized axons may survive for months with the help of 'donated' nuclei.

Action Potentials↗

Decentralization induces long-term c-fos protein-like immunoreactivity in non-neuronal cells in the rat superior cervical ganglion.

The expression of c-fos protein(s) was studied immunohistochemically in the intact and decentralized superior cervical ganglia (SCG) of adult rats. C-fos protein(s)-like immunoreactivity (c-fos-LI) was detected in 1-2% of the principal ganglion cells but not in the satellite or Schwann cells of the intact SCG. After transection of the cervical sympathetic trunk, satellite and Schwann cells in the ganglion expressed c-fos-LI from one hour through 8 days following the operation. The maximal staining was seen 1 day postransection (d.p.t.), when the c-fos-LI was intense throughout the ganglion. No change was observed in the c-fos-LI of the principal neurons. At 8 d.p.t. the number of immunoreactive cells and their staining intensity had decreased, and at 14 d.p.t. they were back to the control level. These results suggest that a long-term expression of c-fos protein(s) is induced in the SCG satellite and Schwann cells after preganglionic denervation possibly related to their activation during nerve degeneration and regeneration.

Animals↗

Recovery of function following unilateral denervation, but not unilateral decentralization, of the pineal gland as indicated by measurements of pineal melatonin content and urinary melatonin metabolites.

The rat pineal gland is an attractive system for studies on the capacity of neural systems to recover following partial injury, allowing both for the creation of precise subtotal lesions and for the measurement of recovery of function at the cellular level. The pineal gland receives overlapping sympathetic innervation from the right and left internal carotid nerves from neurons whose cell bodies are located in the two superior cervical ganglia. This innervation regulates several aspects of pineal metabolism in a circadian fashion, with the most dramatic being a marked increase in the night-time activity of N-acetyltransferase, a key enzyme regulating the rate of melatonin synthesis. We have previously shown that a highly divergent pattern takes place in the night-time activity of this enzyme following two different unilateral lesions of the sympathetic innervation to the gland. Thus, following a unilateral lesion of the internal carotid nerve (unilateral denervation), there is an initial decline in N-acetyltransferase activity; however, normal activity is again seen during the second and subsequent nights. In contrast, a unilateral lesion of the cervical sympathetic trunk, the nerve that innervates the superior cervical ganglion (unilateral decentralization), results in "permanent" impairment of N-acetyltransferase activity. In the present study, we report that the functional capacity of the entire pathway for melatonin synthesis is similarly affected following these lesions, as reflected by the levels of melatonin and of its precursor N-acetylserotonin in the pineal gland, as well as the levels of the main melatonin metabolite 6-hydroxy-melatonin in the urine.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Optimal management of phenylketonuria: a centralized expert team is more successful than a decentralized model of care.

OBJECTIVE: To compare phenylketonuria (PKU) management by a centralized, expert team in the Province of Nova Scotia (NS) with the decentralized approach in New Brunswick (NB). STUDY DESIGN: Retrospective chart review documented frequency of outpatient visits, phenylalanine (Phe) concentration, and medical formula use. Structured telephone interviews with the 8 regional NB dietitians (NB-D) documented their knowledge and support in PKU management. Patients with PKU (n=108; age, birth to 42 years) reside in NB (n=69) and NS (n=39). More were lost to contact in NB than in NS (9/69 vs 1/39) and more were completely off diet in NB than in NS (24/60 vs 1/38, P=.05). All 15 children <2 years old followed by a PKU team in either NS or Saint John, NB had optimal Phe levels. Children 2 to 12 years of age in NS had better Phe control and more medical visits than in NB (P <.01). Older patients had more episodes of elevated Phe levels (P=.01). Formula was dispensed in appropriate yearly amounts to 52% in NB and >95% in NS. Mental handicap or borderline intelligence was common in both NB (44%) and NS (42%). All NB-D wished additional specialized medical, nursing, or social work assistance. CONCLUSIONS: PKU management appears to be more effective with an expert, coordinated team approach.

Adolescent↗

Application of food waste disposers and alternate cycles process in small-decentralized towns: a case study.

The use of food waste disposers (FWDs) can be an interesting option to integrate the management of municipal wastewaters and household organic waste in small towns and decentralized areas. This strategy can be even more environmentally friendly if a suitable treatment process of the resulting sewage is performed in order to control nutrients emission. However, still nowadays, part of the scientific and technical community considers the application of this technology a possible source of problems. In this study, the FWDs were applied, with a market penetration factor of 67%, in a mountain village of 250 inhabitants. Further, the existing wastewater treatment plant (WWTP) was upgraded by applying an automatically controlled alternate cycles process for the management of nutrients removal. With specific reference to the observed results, the impact of the ground food waste on the sewerage system did not show particular solids sedimentation or significant hydraulic overflows. Further, the WWTP was able to face the overloads of 11, 55 and 2g per capita per day of TSS, COD and TN, respectively. Then, the increase of the readily biodegradable COD (rbCOD/COD from 0.20 to 0.25) and the favourable COD/TN ratio (from 9.9 to 12) led to a specific denitrification rate of some 0.06kgNO(3)-N/(kg MLVSS day). Therefore, not only COD removal, but also the total nitrogen removal increased: the denitrification efficiency reached 85%. That led to a better exploitation of the nitrogen-bound oxygen and a consequent reduction of energy requirements of 39%. The final economic evaluation showed the benefits of the application of this technology with a pay back time of 4-5 years.

Biodegradation, Environmental↗

Absence of nutritional or clinical consequences of decentralized bulk food portioning in elderly nursing home residents with dementia in Montreal.

OBJECTIVES: To evaluate the nutritional and clinical consequences of changing from a centralized food delivery system to decentralized bulk food portioning; a system in which meal portioning occurs on residents' floors of a nursing home. DESIGN: A pilot study with a pre-post design SUBJECTS/SETTING: The study took place on one floor of a home for elderly persons with dementia. Of the 34 residents, 22 (1 man) participated in this study. Average age was 82 years (range = 55 to 94 years). Nutritional status was verified before introduction of the bulk food portioning system by 3 nonconsecutive days of observed food intakes, anthropometric measurements (height, weight, triceps skinfold thickness, mid-upper-arm circumference), and biochemical parameters (albumin, lymphocytes, glucose, sodium, potassium, transferrin, vitamin B-12, folate, hemoglobin). Trained dietitians collected the dietary and anthropometric data and validated the food intake estimates and anthropometric measurements. Data were also collected 10 weeks after implementation of the new food distribution system. STATISTICAL ANALYSES PERFORMED: Paired t tests adjusted by a Bonferroni correction assessed differences between values measured before and after introduction of the new food distribution system. RESULTS: Average food consumption increased substantially and significantly after introduction of the bulk food portioning system. Mean energy intakes rose from 1,555 to 1,924 kcal/day and most other nutrients also increased, many significantly, but there were no changes in anthropometric values or biochemical parameters, except for albumin level which decreased to the lower normal limit. APPLICATIONS: Portioning of food in the residents' dining room simulates a homelike atmosphere thereby encouraging increased food consumption. With well-trained and enthusiastic staff, this system could contribute to improved nutritional status in the very elderly, even those who have dementia. Dietitians have a key role to play in overseeing residents' nutritional needs and in training, supervising, and motivating foodservice personnel.

Aged↗

Guide lines for the tuning and the evaluation of decentralized and decoupling controllers for processes with recirculation.

This paper gives guidelines for the pairing, the time response specification, and the tuning for processes with recirculation when decentralized controllers are used. This selection is based on the condition number, which is an indicator of the process directionality, and on the generalized dynamic relative gain (GDRG), which is a measure of the interaction. Simple tuning rules are developed and results are compared to algebraic controllers with decouplers. Performances are evaluated for set-point changes as well as disturbance rejection using the generalized step response (GSR). The GSR gives a 3D graphic of the system response as a function of the input direction.

Journal Article↗