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PubMed2004

[A system for testing alternating frequency properties of body fluid and tissues].

The electric properties of biotic tissues are of importance to our understanding biotic substances even life. But the measurement taken in this aspect is different from the measurement of ordinary materials, we need a special testing instrument for living substances. In order to understand the alternating frequency properties of body fluid and tissues in detail, we have developed an electricity characteristic testing system, which is more proper for testing living substances. This system adopts advanced measuring method and expert circuit. As the measure and the control core, the single chip processor is used. This system has wide frequency range and wide impedance testing range, much more adapted objects, and it is dependable, more precise and intelligent. The application of this system in practical testing has obtained optimal results.

Body Composition↗

PubMed2005

[Niches of several mangrove species in Dongzhai Harbor of Hainan Island].

Employing the succession series of Kandelia candel-Aegiceras corniculatum community in non-indigenous species Sonneratia apetala extension area as resource axes, and with three axes, commonly used calculation formulae, this paper determined the niche breadth and overlap of mangrove populations. The results showed that the niche breadth decreased in order of Aegiceras corniculatum (3.8357) > Kandelia candel (3.3421) > Bruguiera gymnorrhiza (3.3180) > Avicennia marina (3.0975) > Sonneratia apetala (2.9137) > Sonneratia caseolaris (2.5724) > Ceriops tagal (1.8523) > Rhizophora stylosa (1.6897) > Bruguiera sexangula (1.0000), which could indicate the ecological adaptability and distribution range of the species. The niche overlap among K. candel, A. corniculatum, B. gymnorrhiza and A. marina was the largest, suggesting the intense competition among them, followed by the niche overlap of S. apetala with S. caseolaris, A. corniculatum, K. candel and A. marina, S. apetala with R. stylosa and B. sexangula, S. apetala with C. tagal, and S. apetala with B. sexangula.

Ecosystem↗

PubMed1991

Coping with the stress of litigation.

Physicians' responses to the stress of facing a malpractice suit range from energetically adaptive to self-destructive. The course of these responses can be changed with effective intervention and support. Here is some advice including resources to which physicians can turn during such a crisis.

Adaptation, Psychological↗

PubMed1987

[Selectivity of inhibition of pancreatic enzyme secretion after lipase administration into the duodenum].

Administration of lipase into the duodenum inhibits pilase secretion and, to a lesser extent, secretion of proteinases in dogs. The inhibitory effect is prevented by simultaneous administration of cotton oil and hydrolysine acidized up to pH-2. The lipolytic activity of duodenal chyme seems to play a major part in correction of pancreatic juice enzyme range in urgent adaptation of pancreatic secretion to a type of consumed food.

Amylases↗

PubMed1989

Rapid weight loss and lean tissue: evidence for comparable body composition and metabolic rate in differing rates of weight loss.

In assessing the desirability of very low calorie diets (VLCD) it is important to assess whether the additional calorie deprivation associated with a VLCD is within the range of physiological adaptation of normal people: specifically that the overweight person will return to normality in terms of body composition and metabolic rate. Comparison of fat free mass (FFM) and resting metabolic rate (RMR) change was made between two groups of dieting female subjects, whose weight loss was 1.9 kg/week (group A) and 1.1 kg/week (group B) over 8 weeks of diet. Body composition studies showed an equivalent FFM/Wt loss of 0.42 and 0.44 in the high and low weight loss groups respectively. As expected from the greater loss of weight, resting metabolic rate fell further in group A, but the RMR/FFM ratio remained the same (group A 21.3; group B 22.1). There is no evidence to suggest that the rate of weight loss achieved by VLCD is associated with any detriment to body composition or metabolic rate.

Basal Metabolism↗

PubMed1979

[Determination and position of the masticatory surface complex and clinically necessary corrections (with special regard to Fehr's calotte articulation)].

The individual calotte articulation recommended by C. U. Fehr in 1947 has been used at the Free University of W. Berlin for clinical teaching since this time. The following studies were described and/or recalled and contrasted with other methods for determining position: 1. Studies of Grabert mandibular posture compared with the Ivo-Tray model. 2. Stoebe's studies of calottes with various radii, 3. Eichner's and Schmitthelm's roentgencinematographic studies, 4. Reese's study of biting force, 5. Husemann's comparison of different relational determinations, 6. Sauer's study of the success of reocclusion. Based on the clinical results and also the results of difficult comparative studies. we see no reason to depart from functional determination of relation using calotte-shaped, curved wax walls. Clinical example of the grinding surface complex, which is part of the method, guarantees construction of the complete denture within the range of tissue adaptation. No elaborate apparatuses are required. Even complicated tracing methods do not eliminate the possibility of additional work (e.g., removal of pressure areas, reocclusion).

Dental Impression Technique↗

PubMedDate not supplied

Cerebral autoregulation in young spontaneously hypertensive rats. Effect of sympathetic denervation.

Autoregulation of cerebral blood flow was studied with the hydrogen clearance method during development of hypertension in young spontaneously hypertensive rats. To examine the influence of sympathetic nerves on autoregulatory range, the unilateral superior cervical ganglion was removed 2 hours or 2 or 5 weeks before the study. Wall-to-lumen ratio of cerebral arteries was determined with freeze substitution technique. Basal blood pressures were 87 +/- 1 mm Hg (mean +/- SEM) at 4 weeks of age, 105 +/- 2 at 6 weeks, and 126 +/- 3 at 9 weeks, although resting cerebral blood flow was unchanged. Initially, cerebral blood flow remained relatively constant when the blood pressure was raised by intravenous infusion of phenylephrine. The upper limits of cerebral blood flow autoregulation in these groups were 110 +/- 4 mm Hg, 126 +/- 7, and 159 +/- 6 respectively. Acute ganglionectomy significantly lowered the upper limits (p less than 0.05), but chronic denervation did not affect the autoregulatory range. The wall-to-lumen ratios of cerebral arteries were 0.136 +/- 0.007 at 4 weeks and 0.130 +/- 0.005 at 9 weeks. These differences were not significant, nor did sympathetic denervation alter the ratio. These results indicate that (1) the upward shift of the autoregulation is closely related to a rise in the basal blood pressure, (2) acute interruption of sympathetic nerves modulates the autoregulatory range, and (3) adaptation of cerebral blood flow autoregulation to early developmental hypertension may be attributed to factors other than vascular smooth muscle hypertrophy.

Animals↗

PubMed1994

Mental health services in Army primary care: the need for a collaborative health care agenda.

Epidemiologic studies have shown that more than half of mentally ill patients in the United States receive their psychiatric care exclusively in primary care settings. This fraction may be even higher in the military due to concern over possible occupational repercussions resulting from use of specialty psychiatric care and specialist shortages. Collaboration between generalists and mental health care specialists could potentially improve mental health care delivery and reduce psychiatric disability for a large segment of the Army population who have a psychiatric disorder but may not seek specialty care. Collaborative efforts can reinforce military generalists' essential gate-keeping function, thereby decreasing unnecessary medical utilization and health care costs. The authors review the problems associated with mental health care delivery in primary care and provide examples of collaborative models previously studied or currently being explored. A four-part Army Primary Care-Mental Health Services Agenda is proposed, consisting of: (1) coordinated research including primary care-mental health services research and community-based epidemiologic studies; (2) formation of a primary care-mental health services advisory committee for aiding with policy and program development; (3) graduate and continuing medical education in primary care-mental health services emphasizing interdisciplinary collaborative skills; and (4) clinical implementation of feasible collaborative interdisciplinary mental health care models adapted to the range of unique Army primary care settings. The main goal of the Army Primary Care-Mental Health Services Agenda is to improve access to Army mental health care in the most efficacious and cost-effective way and to help minimize the organizational impact of disability related to psychosocial distress.

Cross-Sectional Studies↗

PubMed1995

[Post-traumatic myo-arthropathy of the mandibular joint. Report of a case].

The author reports a case of post-traumatic myoarthropathy which was resolved through the search for a new centric ratio which was subsequently transformed in ICP with a varied vertical dimension. This was based on the assumption that post-traumatic intracapsular modifications impose this therapeutic objective given that they do not fall within the range of muscular adaptability.

Denture, Partial↗

PubMed2006

Management of pediatric radiation dose using GE fluoroscopic equipment.

In this article, we present GE Healthcare's design philosophy and implementation of X-ray imaging systems with dose management for pediatric patients, as embodied in its current radiography and fluoroscopy and interventional cardiovascular X-ray product offerings. First, we present a basic framework of image quality and dose in the context of a cost-benefit trade-off, with the development of the concept of imaging dose efficiency. A set of key metrics of image quality and dose efficiency is presented, including X-ray source efficiency, detector quantum efficiency (DQE), detector dynamic range, and temporal response, with an explanation of the clinical relevance of each. Second, we present design methods for automatically selecting optimal X-ray technique parameters (kVp, mA, pulse width, and spectral filtration) in real time for various clinical applications. These methods are based on an optimization scheme where patient skin dose is minimized for a target desired image contrast-to-noise ratio. Operator display of skin dose and Dose-Area Product (DAP) is covered, as well. Third, system controls and predefined protocols available to the operator are explained in the context of dose management and the need to meet varying clinical procedure imaging demands. For example, fluoroscopic dose rate is adjustable over a range of 20:1 to adapt to different procedure requirements. Fourth, we discuss the impact of image processing techniques upon dose minimization. In particular, two such techniques, dynamic range compression through adaptive multiband spectral filtering and fluoroscopic noise reduction, are explored in some detail. Fifth, we review a list of system dose-reduction features, including automatic spectral filtration, virtual collimation, variable-rate pulsed fluoroscopic, grid and no-grid techniques, and fluoroscopic loop replay with store. In addition, we describe a new feature that automatically minimizes the patient-to-detector distance, along with an estimate of its dose reduction potential. Finally, two recently developed imaging techniques and their potential effect on dose utilization are discussed. Specifically, we discuss the dose benefits of rotational angiography and low frame rate imaging with advanced image processing in lieu of higher-dose digital subtraction.

Body Burden↗

PubMed1995

Changes in retinal time scale under background light: observations on rods and ganglion cells in the frog retina.

The kinetics of rod responses to flashes and steps of light was studied as a function of background intensity (IB) at the photoreceptor and ganglion cell levels in the frog retina. Responses of the rod photoreceptors were recorded intracellularly in the eyecup and as ERG mass potentials across the isolated, aspartate-superfused retina. The kinetics of the retinally transmitted signal was derived from the latencies of ganglion cell spike discharges recorded extracellularly in the eyecup. In all states of adaptation the linear-range rod response to dim flashes could be modelled as the impulse response of a chain of low-pass filters with the same number of stages: 4 (ERG) or 4-6 (intracellular). Dark-adapted time-to-peak (tp, mean +/- SD) at 12 degrees C was 2.4 +/- 0.6 sec (ERG) or 1.7 +/- 0.4 sec (intracellular). Under background light, the time scale shortened as a power function of background intensity, I-bB with b = 0.19 +/- 0.03 (ERG) or 0.14 +/- 0.04 (intracellular). The latency-derived time scale of the rod-driven signal at the ganglion cell agreed well with that of the photoreceptor responses. The apparent underlying impulse response had tp = 2.0 +/- 0.7 sec in darkness and accelerated as I-bB with b = 0.17 +/- 0.03. The photoreceptor-to-ganglion-cell transmission delay shortened by 30% between darkness and a background delivering ca 10(4) photoisomerizations per rod per second. Data from the literature suggest that all vertebrate photoreceptors may accelerate according to similar power functions of adapting intensity, with exponents in the range 0.1-0.2. It is noteworthy that the time scale of human (foveal) vision in experiments on flicker sensitivity and temporal summation shortens as a power function of mean luminance with b approximately 0.15.

Action Potentials↗

PubMed2003

Treadmill walking in incomplete spinal-cord-injured subjects: 1. Adaptation to changes in speed.

UNLABELLED: Walking in spinal-cord-injured (SCI) subjects is usually achieved at a lower speed than in normal subjects. STUDY DESIGN/METHODS: Time and distance parameters, angular displacements of lower limbs and electromyographic (EMG) activity were measured for seven normal and seven SCI subjects at several walking speeds. Analyses of variance were used for comparing groups and speeds. OBJECTIVES: First, to measure the adaptability of SCI subjects' walking pattern to different speeds (0.1-1.0 m/s), and to compare it to that of normal subjects. Second, to characterize SCI subjects' walking pattern as compared to that of normal subjects at a matched treadmill speed (0.3 m/s). SETTING: University-Based Human Gait Laboratory, Montreal, Canada. RESULTS: SCI subjects' pattern adapted to a limited range of speeds. Longer cycle duration, flexed knee at foot contact, increased hip joint flexion at foot contact and during swing, and altered coordination of hip and knee joints were found for the SCI group. At all speeds, duration of muscle activity was longer in the SCI group and the increase in amplitude of soleus EMG activity at higher speeds was not specific to push-off. The importance of matching the walking speed of SCI and normal subjects in order to differentiate the features that are a consequence of SCI subjects' reduced walking speed rather than a direct consequence of the injury is demonstrated. CONCLUSIONS: All SCI subjects could adapt to a narrow range of speeds and only three could reach the maximal tested speed. This limited maximal speed seems to be a consequence of SCI subjects having reached their limit in increasing stride length and not being able to increase stride frequency further. This limitation in increasing stride frequency is likely because of the altered neural drive. SPONSORSHIP: Neuroscience Network of the Canadian Centre of Excellence.

Adaptation, Physiological↗

PubMed1983

Dark adaptation and the acuity/luminance response in senile macular degeneration (SMD).

Patients with senile macular degeneration (SMD) often complain of problems with adaptation and have best acuity under a restricted range of lighting conditions. We investigated dark adaptation and acuity over a wide range of luminances in eight SMD patients and six age-matched controls. Some patients showed evidence of altered dark adaptation, with a much longer time required to reach asymptotic sensitivity levels than shown by normals; others had difficulty with spatial resolution at different light levels. There was good correlation between symptoms and test findings; all but one patient who reported difficulties with adaptation demonstrated either retarded adaptation, aberrant acuity/luminance response, or both. These data provide evidence that the processes which adjust the sensitivity of the retina and the spatial summation properties of the retina are disrupted in SMD.

Aged↗

PubMed2006

Functional neuroimaging of emotional learning and autonomic reactions.

This article provides a selective overview of the functional neuroimaging literature with an emphasis on emotional activation processes. Emotions are fast and flexible response systems that provide basic tendencies for adaptive action. From the range of involved component functions, we first discuss selected automatic mechanisms that control basic adaptational changes. Second, we illustrate how neuroimaging work has contributed to the mapping of the network components associated with basic emotion families (fear, anger, disgust, happiness), and secondary dimensional concepts that organise the meaning space for subjective experience and verbal labels (emotional valence, activity/intensity, approach/withdrawal, etc.). Third, results and methodological difficulties are discussed in view of own neuroimaging experiments that investigated the component functions involved in emotional learning. The amygdala, prefrontal cortex, and striatum form a network of reciprocal connections that show topographically distinct patterns of activity as a correlate of up and down regulation processes during an emotional episode. Emotional modulations of other brain systems have attracted recent research interests. Emotional neuroimaging calls for more representative designs that highlight the modulatory influences of regulation strategies and socio-cultural factors responsible for inhibitory control and extinction. We conclude by emphasising the relevance of the temporal process dynamics of emotional activations that may provide improved prediction of individual differences in emotionality.

Animals↗

PubMed1990

[Difference in responses of free nerve endings and Ruffini-type endings innervating the cat mandibular periosteum to square wave pressure stimuli, ramp mechanical stimuli and triangular vibrations].

UNLABELLED: The free nerve endings and Ruffini type endings in the cat mandibular molar buccal periosteum (posterior periosteum) were selectively stimulated with specific displacements of various velocities and frequencies and the afferent impulses generated by the nerve endings were recorded. RESULTS: 1. There were two types of fast-adapting free nerve endings, discharging on effects and off-effects in response to square wave pressure stimuli and ramp mechanical stimuli and on-effects only. 2. Unencapsulated endings were distributed near the mentale foramen and again there were two types of fast adapting endings, discharging on effects and off effects in response to square wave pressure stimuli and ramp mechanical stimuli, and on-effects only. 3. Slow-adapting free nerve endings were also observed through response to square wave pressure stimuli and ramp shaped pressure stimuli. These were difficult to differentiate from the slow adapting Ruffini-type endings. 4. Ruffini type endings were slow adapting types, exhibiting impulse frequency displacement velocity curves of F = 39.627V0.743 (F = impulse frequency, V = displacement velocity, r = 0.999, n = 12 and p less than 0.001). The number of impulse displacement curves was proportional to the displacement, with F = 1.024S0.767 (F = impulse frequency, S = displacement, r = 0.981, n = 6 and p less than 0.001). 5. Free nerve endings followed Stevens' power function law, dropping in order from fast-adapting units (10 units) to intermediate type sensory units (21 units) and slow-adapting sensory units (20 units), with 0.894 +/- 0.103, 0.684 +/- 0.022 and 0.650 +/- 0.023, respectively. Values for slow adapting Ruffini type endings followed the previous order. 6. Slow adapting free nerve endings responded to triangular vibration stimuli at 0.1 Hz to 240 Hz and the lower frequency limit of 0.1 Hz (actually it was below 0.1 Hz but this value was adopted in order to facilitate the recording of the difference to fast adapting free nerve endings) was considerably lower than the 0.6 Hz to 1 Hz range for fast-adapting free nerve endings. The structure and functions of the nerve endings in the cat posterior periosteum were investigated and it was found that the relationship between the impulse frequency and displacement velocities and displacement amplitude for slow-adapting Ruffini-type endings followed Stevens' power factor law. In conclusion, it was demonstrated that the slope constant follows the order of fast-adapting free nerve endings, intermediate type free nerve endings and slow-adapting free nerve endings.

Animals↗

PubMed1998

Quantification of toxic cyanobacteria in water by use of competitive PCR followed by sequence-specific labeling of oligonucleotide probes.

A complete nucleic-acid-based assay which consists of sample preparation, DNA amplification, and chromogenic detection was developed for quantifying potential toxin-producing cyanobacteria of interest to the public. The sample preparation strategy involves the same solid phase for cell concentration and DNA purification. For the detection step, we used a combination of competitive PCR amplification, sequence-specific labeling of oligonucleotide probes, hybridization of the labeled oligonucleotides to immobilized complements and, finally, chromogenic detection. The complete assay was tested with water containing toxin-producing cyanobacteria belonging to the genus Microcystis. A detection limit of 100 cells/ml and a quantitative range of more than 3 orders of magnitude were obtained. This approach can easily be adapted to a wide range of bacterial species and has the potential for simultaneous detection and quantitation of several different target organisms by a single assay.

Cyanobacteria↗

PubMed1985

Computer-aided thermographic evaluation of disturbances of the coronary adaptive reserve: an experimental study.

Brief episodes of severe ischaemic loads have been reported to attenuate or abolish the vascular autoregulatory capacity, including reactive hyperaemic vasodilation, in the coronary bed. It is suggested that the developed loss of the coronary adaptive reserve and the consecutive ultrastructural alterations can be considered an experimental model for the human effort anginal attacks occurring without significant mechanical constriction of the vessels. The functional morphologic patterns in this state were analysed by the new quantitative technique which is based on the computerized evaluation of cardiac thermograms taken with a thermovision (AGA 750) equipment. In the isolated perfused heart of rabbits, the total adaptive loss developed in the overall flow (cessation of reactive hyperaemia) was found to be associated with slow reacting coronary vessels in the cardiac surface, a delayed shift of the computerized thermographic profiles to warmer ranges during reactive hyperaemia. The pattern strongly suggested a redistribution of flow from the subendocardium. In further observations, simulated emergency coronary bypass operations on dog hearts revealed another distinct thermographic pattern: a reduced vascular adaptive range without considerable delay in reactivity. The studies demonstrated the usefulness of quantitative thermography in visualising and differentiating the various types of coronary dysfunction.

Adaptation, Physiological↗

PubMed1989

Chemical specificity of short-chain fatty acid-induced electrogenic secretory response in the rat colonic mucosa.

1. Luminal additions of normal short-chain fatty acids (SCFA: 3-6 carbons) increased transmural potential difference (PD: lumen negative) across rat everted colon in a dose-dependent manner. 2. The PD response to SCFA adapted rapidly and was not evoked by further cumulative addition of the same acid (self-adaptation) or different acids (cross-adaptation). 3. A broad range of SCFA derivatives were tested as potential stimulators of the PD response and cross-adaptation with propionate: a single carboxyl group and 3-6 carbon-chain were an absolute requirement for recognition. 4. These results suggest that SCFA-reception mechanism of the rat colonic mucosa has some sort of chemical specificity for stimulating electrogenic secretory response.

Amino Acids↗