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PubMed2000

Clinical applications of multifocal electroretinography.

The multifocal ERG using the m-sequence stimulation technique allows the derivation of 61 - 241 local ERG signals in a central visual field of about 60 degree diameter in a short time between 4 and 16 min. A recording in a light adapted state offers local information comparable to cone responses in the full-field ERG. Retinal functional losses due to regional disorders in outer retinal layers can be described in detail with this technique. In maculopathies decreased or absent central ERGs are found surrounded by normal ERG. The extent of the central lesion can be estimated. In diseases of the outer retina the pattern of distribution of multifocal ERG activity is similar to the the pattern of the visual field defect. In addition to decreased ERG amplitudes a delay of implicit time may be an important sign of pathology, i.e. the pronounced delay of implicit times in the periphery in retinitis pigmentosa and the implicit time delays in regions associated with retinal edema like CRVO and cystoid macula edema in intermediate uveitis. No simple correlation of the first order kernel multifocal ERG and field defects could be found in disorders of the ganglion cell layer. The multifocal ERG is therefore useful in the differential diagnosis of retinal and optic nerve diseases.

Diabetic Retinopathy↗
PubMed2002

The effectiveness of community-based interventions to improve maternal and infant health in the Northeast of Brazil.

OBJECTIVE: To evaluate the effectiveness of a community-based intervention project aimed at reducing maternal and infant mortality in a poor urban district in the city of Natal, in the Northeast of Brazil. METHODS: The intervention, called the ProNatal project, introduced a program of integrated community health care to a geographically defined population. The interventions included the establishment of antenatal clinics at the district's health centers, the opening of the maternity facilities at the polyclinic for low-risk deliveries, the introduction of a family planning clinic and a breast-feeding clinic, support from pediatricians for under-5 (well-baby) clinics, children's outpatient services and children's emergency care, and the introduction of health agents recruited from the local community. Representative surveys of the population were taken at the project's inception (July 1995) and then 30 months later (December 1997), using a general health questionnaire adapted to the local conditions. Mortality data were collected from local registration systems as well as from an autopsy survey of perinatal and infant deaths. RESULTS: During 1995 there were 4 maternal deaths from 1 195 pregnancies (maternal mortality of 335/100 000); three of the deaths were related to hypertension and one to uterine perforation after an illegal abortion. During 1998 (post-intervention), there were no maternal deaths in pregnancy or childbirth. In 1993 no deliveries took place at the polyclinic, but in 1998 there were 946 deliveries at the clinic without any serious complications. The method of delivery, the incidence of prematurity, and the incidence of low birthweight did not change significantly over the study period. In the post-intervention survey, 75% of women reported receiving contraceptive advice from a doctor in the preceding year, compared to 50% in the first sample. A mortality survey carried out in 1993-1995 estimated the infant mortality rate to be 60/1 000 live births. By 1998, using data collected locally by active surveillance, the infant mortality rate was 37/1 000 live births. The causes of infant death in both those periods were dominated by respiratory infections and diarrheal disease. Over 95% of both samples initiated breast-feeding, but a higher proportion of the post-intervention sample reported breast-feeding for longer than 6 months (41% vs. 32%, P = 0.0005). No differences were apparent in the use of under-5 clinics, but immunization rates improved. Post-intervention, significant improvements were documented in the mothers' understanding of basic hygiene, their knowledge of causes of common diseases, and their management of acute respiratory infections and diarrhea in children. This was particularly true for the households visited by a community health agent. CONCLUSIONS: Inequalities in health care in poor urban populations can be reduced by integrated community-based interventions, including the use of health agents recruited from the local community.

Brazil↗
PubMed2001

[Treatment of Ewing's sarcoma with 2 different protocols].

Since 1985, 54 with localized Ewing's sarcoma of bone were treated at the Onco-Orthopedics Clinic of the Sofia University Hospital (Sofia, Bulgaria). Thirty-two patients received the classical four-drug combination with doxorubicin, dactinomycin, vincristine, and cyclophosphamid. The last 22 patients were treated with six-drug protocols where cisplatinium and ifosfamid were added to the standard four-drug regimens. Local treatment was adapted to the age of the patient and the location and volume of the tumor. Fourteen patients received radiotherapy alone, 24 postoperative radiotherapy and 16 surgery alone as local treatment. At a mean follow-up of 6 years, the disease free survival rate reached 44%. Eleven patients had a good local response and 25 developed metastatic disease. Statistical analysis confirmed the deleterious effect of pelvic localizations and large tumor volume on prognosis and demonstrated the dramatic improvement obtained with the six-drug protocol (5-year disease free survival 61% versus 23%) and surgery (61% versus 25%).

Adolescent↗
PubMed1984

Local application of PGE2 by means of a portio-adapter. A new method of induction of labor.

In 206 pregnant women with unfavorable cervix, labor was induced by local application of 1.5 mg PGE2 by means of a portio-adapter. In 70.4% labor was successfully induced after a single "PG-cap". An additional 11.6% went into labor after a second or third cap. In 14.1%, a sufficient priming of the cervix was obtained and amniotomy was performed. 3.9% had to be considered failures. The overall incidence of operative deliveries was 17%. Apgar scores and cord gases were within normal ranges. Internal tocography revealed a physiologic pattern of contractions with slightly elevated maximal pressures but normal baseline values. With local application of PG by means of a portio-adapter the preparation of a gel mixture can be avoided and the exact anatomic location of the PG-containing solution allows a withdrawal in case of hyperstimulation. From the results of this study it is concluded that local application of 1.5 mg PGE2 by means of a portio-adapter is a safe and effective method of induction of labor.

Cervix Uteri↗
PubMed2004

Multiple sites of adaptive plasticity in the owl's auditory localization pathway.

In the midbrain auditory localization pathway of the barn owl, a map of auditory space is relayed from the external nucleus of the inferior colliculus (ICX) to the deep and intermediate layers of the optic tectum (OT) and from these layers to the superficial layers. Within the OT, the auditory space map aligns with a visual map of space. Raising young barn owls with a prismatic displacement of the visual field leads to progressive changes in auditory tuning in the OT that tend to realign the auditory space map with the prismatically displaced visual space map. The only known site of this adaptive plasticity is in the ICX, in which the auditory system first creates a map of space. In this study, we identified an additional site of plasticity in the OT. In owls that experienced prisms beginning late in the juvenile period, adaptive shifts in auditory tuning in the superficial layers of the OT exceeded the adaptive shifts that occurred in the deep layers of the OT or in the ICX. Anatomical results from these owls demonstrated that the topography of intrinsic OT connections was systematically altered in the adaptive direction. In juvenile owls, plasticity in the OT increased as plasticity in the ICX decreased. Because plasticity at both sites has been shown to decline substantially in adults, these results suggest that an age-dependent decrease in auditory map plasticity occurs first in the ICX and later at the higher level, in the OT.

Acoustic Stimulation↗
PubMed1989

[Compensatory-adaptive reactions of epithelial barriers and cellular systems of local immunity].

Experimental data show that environmental chemical factors cause the development of standard compensatory and adaptative processes in the system of epithelium barriers and cells of mesenchymal genesis. Compensatory and adaptative shifts are carried out parallel to an increase in the quantitative composition of cells due to the intensification of DNA-synthesizing activity and cytokinetic reactions, along with raising their structural and functional activity. Correlation between a number of systems of cell protection has been established.

Adaptation, Physiological↗
PubMed2006

The evolution of human fatness and susceptibility to obesity: an ethological approach.

Human susceptibility to obesity is an unusual phenomenon amongst animals. An evolutionary analysis, identifying factors favouring the capacity for fat deposition, may aid in the development of preventive public health strategies. This article considers the proximate causes, ontogeny, fitness value and evolutionary history of human fat deposition. Proximate causes include diet composition, physical activity level, feeding behaviour, endocrine and genetic factors, psychological traits, and exposure to broader environmental factors. Fat deposition peaks during late gestation and early infancy, and again during adolescence in females. As in other species, human fat stores not only buffer malnutrition, but also regulate reproduction and immune function, and are subject to sexual selection. Nevertheless, our characteristic ontogenetic pattern of fat deposition, along with relatively high fatness in adulthood, contrasts with the phenotype of other mammals occupying the tropical savannah environment in which hominids evolved. The increased value of energy stores in our species can be attributed to factors increasing either uncertainty in energy availability, or vulnerability to that uncertainty. Early hominid evolution was characterised by adaptation to a more seasonal environment, when selection would have favoured general thriftiness. The evolution of the large expensive brain in the genus Homo then favoured increased energy stores in the reproducing female, and in the offspring in early life. More recently, the introduction of agriculture has had three significant effects: exposure to regular famine; adaptation to a variety of local niches favouring population-specific adaptations; and the development of social hierarchies which predispose to differential exposure to environmental pressures. Thus, humans have persistently encountered greater energy stress than that experienced by their closest living relatives during recent evolution. The capacity to accumulate fat has therefore been a major adaptive feature of our species, but is now increasingly maladaptive in the modern environment where fluctuations in energy supply have been minimised, and productivity is dependent on mechanisation rather than physical effort. Alterations to the obesogenic environment are predicted to play a key role in reducing the prevalence of obesity.

Adipose Tissue↗
PubMed1988

Environmental contamination by heavy metals and fluoride in the Saeftinge salt marsh (The Netherlands) and its effect on sheep.

The Saeftinge salt marsh in the Westerschelde estuary (southwestern part of the Netherlands) represents one of the very few tidal brackish marsh ecosystems in Western Europe. From May 1983 to May 1985 the local pollution of this marsh with metals and fluoride was investigated. Samples from soil and vegetation were analysed monthly for cadmium, lead, copper, zinc, manganese, iron, and fluoride. The amount of these substances in the soil appeared to be related to both the percentage of clay particles and organic matter in the soil and to the frequency of tidal submergences. In vegetation, the pollutants clearly showed a seasonal variation. Adherent clay, deposited on the plants during submergences, contributed considerably to the total amount of these elements. Sheep grazing in the marsh were investigated for renal and faecal excretion of these elements, but no relation between these samples and the seasonal variation in vegetation was found. Presumably sheep consumed vegetation selectively, avoiding the more contaminated plants. Regular clinical inspections of the sheep revealed no signs of acute or chronic intoxication. The organs of sheep that died during the investigation showed increased levels of cadmium in the liver and kidney, and iron in the liver, but not enough to cause alarm. Fluoride found in the rib material, although slightly increased, did not indicate fluorosis. In conclusion, contamination with metals and fluoride, as observed in the salt marsh, apparently does not impair the health of locally grazing sheep. This may be due to selective consumption behaviour of the sheep, their stabling during the winter, limited biological availability of the elements studied, and a sheep management adapted to the local circumstances.

Animals↗
PubMed2002

Preparing for change in the secondary prevention of coronary heart disease: a qualitative evaluation of cardiac rehabilitation within a region of Scotland.

BACKGROUND: Secondary prevention of Coronary Heart Disease (CHD) is often poorly managed and its benefits attained in only a minority of those with CHD. Guidelines developed in the United Kingdom and North America suggest that in future cardiac rehabilitation programmes should provide services through individualized programmes that cater for a wide range of conditions associated with CHD. This will involve substantial and costly changes to current programmes that are mostly standardized and for postmyocardial infarction patients. Based on change theory, this study examined the dynamics, strengths and weaknesses of an existing programme in a Scottish region which was due to undergo the changes suggested by guidelines. AIM: To examine the perceived provision of secondary prevention services for CHD from the perspectives of health professionals within one region in the West of Scotland. METHODS: A purposive sample of 14 health professionals (eight primary and six secondary care health professionals) was selected to cover a range of professional roles including both specialists and generalists. Separate focus group discussions (2) were held with primary care and secondary care professionals. FINDINGS: Whilst the health professionals were enthusiastic about CHD prevention and their involvement, they perceived barriers to the success of the existing service as being complex and multifactorial, including patient, social and service-related factors. Although both groups identified motivation as the most influential personal factor, secondary care staff tended to focus on the importance of patient factors in influencing motivation to change, whereas the primary care staff referred more to the cumulative effects of social and cultural factors. Professionals highlighted weaknesses in the transition between hospital and community-based services with regard to the information flow between primary and secondary care. CONCLUSIONS: Although the study has immediate relevance for the local area, it highlighted issues of more general relevance to cardiac rehabilitation programme development and intersectoral working, such as communications and role perceptions in multi-professional working and the need to adapt services to local socio-economic conditions.

Communication↗
PubMed2004

Temporal kinetics of the light/dark translocation and compartmentation of arrestin and alpha-transducin in mouse photoreceptor cells.

PURPOSE: To determine the temporal kinetics of the simultaneous translocation of arrestin and rod alpha-transducin in mice exposed to different lighting environments and to compare the subcellular compartmentation of cone alpha-transducin with arrestin. METHODS: Double labeling immunofluorescence microscopy and image analysis are used to visualize and quantify the concentrations of rod arrestin and alpha-transducin in the subcellular compartments of the rod outer segments, the rod inner segments and the synaptic terminals. RESULTS: The magnitude of the effects of the translocation are clearly contrasted in images of the retinas of animals that have been maximally light adapted verses retinas that have been maximally dark adapted. The onset of light results in a rapid, simultaneous, translocation of arrestin and alpha-transducin from their respective compartments (alpha-transducin in the rod outer segment and arrestin in the rod inner segment) to the opposite compartment. Almost all of alpha-transducin has translocated in less than two min whereas the translocation of the majority of arrestin requires at least five to six min. Translocation in the opposite direction, from light to dark, occurs more slowly for both proteins with arrestin requiring almost 30 min and alpha-T needing more than 200 min to complete its journey. Under the same lighting conditions, cone arrestin translocation is incomplete. Cone alpha-transducin does not translocate under any the lighting conditions tested. Unlike the frog, continuous exposure of mice to light does not result in arrestin translocating back to the rod inner segment. CONCLUSIONS: These data suggest that there are four mechanisms involved in the translocation of these two proteins. They also support the conclusion that the more important cellular function of the translocation process is to terminate phototransduction in rod and cone photoreceptors, which could provide protection against light damage. The secondary function of translocation is to maximize rod sensitivity to light during dark adaptation. The restricted localization of cone alpha-transducin to the cone outer segment is consistent with the function of cones in bright light, just as the concentration of rod alpha-transducin in dark adapted rod outer segment is consistent with their functioning in dim light.

Animals↗
PubMed1996

Force, development, and neoplasia: development from another perspective as illustrated through a study of in vitro plant development from neoplasm.

Differentiation from the neoplastic state can be a dynamic adaptation to the localized stress of increasing cohesive forces in tissue. Repulsive forces, occurring within and between cells, are seen as leading to de-differentiation into the neoplastic state or neoplasm. During early development, especially where and when mitosis occurs frequently, cohesive and repulsive forces may necessarily coexist in oscillating degrees. Correspondingly, cohesive-force and repulsive-force generating metabolites may co-exist in oscillating concentrations. Cancer or neoplasia occurs, according A. Szent-Gyorgyi, when cohesiveness breaks down locally, probably thru the conversion of methylglyoxal into lactic acid. Cancer may also occur due to the accumulation of such putatively, repulsion-generating factors as lactic acid. Plant tumors in vitro respond adaptively to cohesion-generating chemicals, such as ascorbic acid and methylglyoxal, by generating buds, embryos, and plantlets.

Adaptation, Physiological↗
PubMed2002

Co-adaptation between cassava mosaic geminiviruses and their local vector populations.

Four cassava mosaic geminivirus (CMG) isolates; African cassava mosaic virus from Namulonge, Uganda (ACMV-[Nam]), East African cassava mosaic virus from Mtwara, Tanzania (EACMV-[Mtw]), EACMV-Uganda from Namulonge (EACMV-UG[Nam]) and Indian cassava mosaic virus from Trivandrum, India (ICMV-[Tri]) were compared for their ability to be transmitted by four colonies of cassava whitefly, Bemisia tabaci (Gennadius), collected from Namulonge (NAM), Mtwara (MTW), Kumasi (KUM) and Trivandrum (TRI). With 20 adult whiteflies per test plant, the CMGs from Africa were transmitted by all three of the African B. tabaci populations to 60-79% of the target plants. Indian cassava B. tabaci transmitted ICMV-[Tri] to 89% of the target plants. In contrast, Indian cassava B. tabaci transmitted EACMV-[Mtw] and Tanzanian cassava B. tabaci transmitted ICMV-[Tri] less than a tenth as often, even when using 50 adults per plant and with increased acquisition and inoculation access periods. The complete coat protein genes of the CMGs had sequences typical of their source viruses, the major differences occurring between those originating from India and Africa. Symptom severity of the CMGs was quantified precisely by both visual assessment and image analysis techniques. EACMV-[Mtw] and ACMV-[Nam] were the most and least damaging isolates with 15.4 and 10.0% of the leaf area diseased, respectively. In these tests the transmission frequency was not linked to symptom severity in the source plants. These data support the hypothesis that virus-vector co-adaptation exists in the cassava mosaic disease (CMD) pathosystem and the results are discussed in relation to CMD epidemiology.

Adaptation, Biological↗
PubMed1991

Health services reform in Poland: issues in recent developments.

After ten years of debate and discussion, the political situation within Poland finally allows the possibility to implement basic reforms in the health care system. Parallel development of the political and technical aspects of the reform has now lead to a final proposal for fundamental reforms in health system responsibility, financing and management. This article describes the current conceptual developments and the political and social context for these final reform proposals at the time of their submission to the government. The primary changes suggested are aimed at increasing the awareness of local, regional and national administrations, health care professionals and the general public that health care has a cost, and that resources must be used carefully if they are to cover health needs. In addition, 'health care' as a term must be extended to include factors and activities besides direct medical services. Such factors as air and water quality, diet, smoking and alcohol consumptions are examples of matters which will also be included in the focus of health system planners. A key element of the organisational reforms is decentralisation of responsibility for health care planning and administration within the framework of nationally set standards and priorities. Based on local decisions, the current basic organisation unit of health care delivery, the ZOZ or integrated health care units, will be redefined and either decomposed into their component services or receive newly defined responsibilities more adapted to the local realities of available manpower and medical facilities. In addition, the development of a private health care sector complementing and even competing with the public services sector will be actively encouraged.

Government↗
PubMed2001

Spatial scale and cellular substrate of contrast adaptation by retinal ganglion cells.

Human visual perception and many visual system neurons adapt to the luminance and contrast of the stimulus. Here we describe a form of contrast adaptation that occurs in the retina. This adaptation had a local scale smaller than the dendritic or receptive fields of single ganglion cells and was insensitive to pharmacological manipulation of amacrine cell function. These results implicate the bipolar cell pathway as a site of contrast adaptation. The time required for contrast adaptation varied with stimulus size, ranging from approximately 100 ms for the smallest stimuli, to seconds for stimuli the size of the receptive field. The differing scales and time courses of these effects suggest that multiple types of contrast adaptation are used in viewing natural scenes.

Adaptation, Ocular↗
PubMed1994

Motion aftereffects with random-dot chequerboard kinematograms: relation between psychophysical and VEP measures.

A random-dot chequerboard kinematogram was used to investigate the effect of motion adaptation both on evoked potentials and on motion aftereffects (MAEs). The experimental paradigm used allowed simultaneous measurement of both variables. Each adaptation period was followed by a series of 5 short test stimuli to which evoked potentials were recorded. Motion aftereffects were observed in the intervals between test stimuli. An inverse relationship between mean N2-P1 amplitude and mean reported MAEs was found as a function of adaptation durations of 1.4, 5.6, and 17.5 s. When the shortest and longest adaptation durations were compared, this relationship held for thirteen of fourteen subjects tested when adaptation-motion and test-motion directions corresponded and for twelve of fourteen subjects when they were opposed. The possibility that the effect of motion adaptation on N2-P1 amplitude was due to local luminance-contrast adaptation is discussed and shown to be unlikely. The suitability of this paradigm for the combined psychophysical and electrophysiological assessment of disturbances in motion perception is discussed.

Adolescent↗
PubMed1983

Specificity of physiologic adaptations resulting from ice-hockey training.

The specificity of the metabolic and cardiorespiratory responses to varied seasonal training programs and to varied testing modalities and protocols were investigated in two groups of college hockey players. Training consisted of either ice hockey (IH) or a combination of ice hockey and prolonged low-intensity cycling (IH-C). Measurement of training-induced adaptations were determined during maximal and submaximal ice skating, and during maximal and submaximal cycling. Ice hockey training caused no change in VO2max, maximal heart rate (HRmax), and maximal ventilation (VEmax) during maximal ice skating. During submaximal ice skating following IH training, however, reductions (P less than 0.05) in blood lactate (La), VE/VO2, and respiratory exchange ratio (R) were observed. When maximal and submaximal cycling was employed as the test modality, no training-induced alteration was found. The IH-C training program (ice hockey-cycling) resulted in adaptations similar to those observed during submaximal ice skating following the IH training. In addition, a reduction (P less than 0.05) in heart rate was observed during submaximal cycling exercise. From these findings it appeared that the adaptive response to training may be specific to the type of work used in training, the type of ergometry used to evaluate training, and to specific physiological processes. In addition, these results suggested a dissociation between local and central adaptations.

Adult↗
PubMed1969

The mechanoreceptors of the costo-vertebral joints.

1. Unitary recording in the thoracic dorsal roots of mechanoreceptor discharges from the costo-vertebral joints was carried out in the cat and rabbit. Criteria for the identification of costo-vertebral joint mechanoreceptors were established.2. The majority of rib joint mechanoreceptors are slowly adapting and fifty-three such receptors were studied. Five rapidly adapting receptors were also identified.3. The responses of these receptors have been correlated with rib position and movement. The slowly adapting receptors gave a monotonic response to different rib positions. 72% showed an increase of discharge rate with displacements towards expiratory rib positions.4. In response to manually imposed rib movements slowly adapting joint mechanoreceptors gave a dynamic response which was directly related to the velocity of the movement and adapted within 2 sec. The movements of breathing produced a corresponding alteration of the discharge frequency of the slowly adapting receptors.5. Slowly adapting receptors were localized to the capsule of the costo-transverse joint by probing. They responded to increased intra-articular pressure with an increase of discharge rate and were silenced by intra-articular lignocaine, 0.4%.6. Rapidly adapting joint mechanoreceptors responded to rib movement with a brief burst of discharges.7. The rib joint mechanoreceptors signal rib joint position, and the direction and velocity of rib movement. It is suggested that these afferent discharges provide the basis for the perception of respiratory movements of the chest. The significance of these receptors to the ;sense of effort' resulting from a resistance to breathing is discussed.

Action Potentials↗