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PubMedDate not supplied

Case control study of neuroblastoma in west-Germany after the Chernobyl accident.

BACKGROUND: To explore possible causes of a 1988 incidence peak of infant neuroblastoma in west German regions which were contaminated with more than 6000 Bq/m2 Cs137 from the Chernobyl accident. The primary working hypothesis was that parents of the diseased children had been contaminated by an excessive intake of locally produced food, especially mushrooms or deer. DESIGN: Case control study with 1:2 (cases:controls) matching. Data were collected from the children's parents by questionnaires and telephone interviews. SETTING: Nation-wide study (former FRG) based on the German Childhood Cancer Registry. SUBJECTS: Cases born in 1988 and reported with a neuroblastoma to the registry until March 1992. Population-based healthy controls, matched for age, sex and residence at time of diagnosis. RESULTS: The working hypothesis could not be confirmed by the study, because the parents of cases tended to eat less locally grown food than the parents of controls (RR = 0.63, 95% CI:0.20-1.97). Possible influence factors which previously have been described to be associated with neuroblastoma incidence could not be confirmed by the study. Parental exposure to herbicides and pesticides was associated with the occurrence of neuroblastoma (RR = 4.2, 95% CI:1.4-12.9). Neuroblastoma stage distribution in the contaminated regions was shifted towards lower stages as compared to the less contaminated regions and previous age cohorts. CONCLUSIONS: The study does not show additional evidence that the observed increase in neuroblastoma incidence might have been caused by exposure to fallout from the Chernobyl accident. The observed shift towards lower clinical stages may rather indicate increased diagnostic awareness. The association between neuroblastoma and parental exposure with herbicides and pesticides resulted from an extensive exploratory data analysis and needs to be confirmed in further studies.

Child, Preschool↗
PubMed1988

Cellular retinoic acid binding protein: detection and quantitation in regenerating axolotl limbs.

The concentrations of apo (unoccupied), holo (occupied), and total cellular retinoic acid binding protein (CRABP) were measured at various stages of axolotl limb regeneration. The ratio of apo-CRABP to holo-CRABP declined with advancing regenerate stage until the CRABP was all in the holo form. The increase in holo-CRABP is correlated with a stage-dependent shift in the effect of exogenous retinoic acid on regenerate pattern, from pattern duplication to inhibition of regeneration. The data suggest, though they do not prove, that these different morphological effects could be due to a shift from a CRABP-dependent to a CRABP-independent mechanism of exogenous retinoic acid (RA) action that is related to stage-specific variations in endogenous RA levels.

Ambystoma↗
PubMed1990

Sleep disturbances in HIV-infected homosexual men.

To provide a better understanding of the etiology of subjective sleep complaints in HIV-infected individuals, a study to evaluate sleep/wake disturbances in 10 healthy HIV-infected male volunteers was performed. All subjects were HIV-infected but had no history of AIDS-related infections, and considered clinically asymptomatic. Interviews and sleep questionnaires revealed sleep complaints in nine subjects. Five healthy HIV-seronegative male subjects, with no history of sleep complaints, were also evaluated. Sleep architecture analyses detected that, in comparison to published normative data and to negative controls, there was a significant increase in the total percentage of slow wave sleep (SWS) and an increase in the percentage of SWS in the later sleep cycles. When compared with normative data, an increase in stage 1 shifts, rapid eye movement (REM) periods, and arousals were also observed in the HIV-infected group. Significant decreases in sleep latency, total percentage stage 2 sleep, and average REM durations were also observed in the HIV-infected group compared with normative data. These sleep architecture abnormalities could not be attributed to known sole primary sleep disorders, first night effect, medications, anxiety or depression. This study indicates that sleep disturbances occur early in the course of HIV infection and suggests that the observed alterations of sleep physiology may be a consequence of central nervous system involvement and/or immune defense mobilization in the early phases of HIV infection.

Adult↗
PubMed1996

An in vitro model for sequential study of shiftdown of Mycobacterium tuberculosis through two stages of nonreplicating persistence.

It was demonstrated previously that abrupt transfer of vigorously aerated cultures of Mycobacterium tuberculosis to anaerobic conditions resulted in their rapid death, but gradual depletion of available O2 permitted expression of increased tolerance to anaerobiosis. Those studies used a model based on adaptation of unagitated bacilli as they settled through a self-generated O2 gradient, but the model did not permit examination of homogeneous populations of bacilli during discrete stages in that adaptation. The present report describes a model based on culture of tubercle bacilli in deep liquid medium with very gentle stirring that keeps them in uniform dispersion while controlling the rate at which O2 is depleted. In this model, at least two stages of nonreplicating persistence were seen. The shift into first stage, designated NRP stage 1, occurred abruptly at a point when the declining dissolved O2 level approached 1% saturation. This microaerophilic stage was characterized by a slow rate of increase in turbidity without a corresponding increase in numbers of CFU or synthesis of DNA. However, a high rate of production of glycine dehydrogenase was initiated and sustained while the bacilli were in this state, and a steady ATP concentration was maintained. When the dissolved O2 content of the culture dropped below about 0.06% saturation, the bacilli shifted down abruptly to an anaerobic stage, designated NRP stage 2, in which no further increase in turbidity was seen and the concentration of glycine dehydrogenase declined markedly. The ability of bacilli in NRP stage 2 to survive anaerobically was dependent in part on having spent sufficient transit time in NRP stage 1. The effects of four antimicrobial agents on the bacilli depended on which of the different physiologic stages the bacilli occupied at a given time and reflected the recognized modes of action of these agents. It is suggested that the ability to shift down into one or both of the two nonreplicating stages, corresponding to microaerophilic and anaerobic persistence, is responsible for the ability of tubercle bacilli to lie dormant in the host for long periods of time, with the capacity to revive and activate disease at a later time. The model described here holds promise as a tool to help clarify events at the molecular level that permit the bacilli to persist under adverse conditions and to resume growth when conditions become favorable. The culture model presented here is also useful for screening drugs for the ability to kill tubercle bacilli in their different stages of nonreplicating persistence.

Adenosine Triphosphate↗
PubMed1977

Effects of prestriate, inferotemporal, and superior temporal sulcus lesions on attention and gaze shifts in rhesus monkeys.

The role of extrastriate cortical areas in selective attention was studied in 12 rhesus monkeys. Animals learned a series of color-form pattern discrimination problems, with either color or form cues relevant. After each problem was mastered, correct behavior required a shift in attention, i.e., that responses be made to be previously irrelevant dimension. On some problems shifting attention required that the animal maintain the same fixation; on other problems the color and form cues were separated in space, and the attention shift presumably required a shift in gaze. Matched groups of animals with inferotemporal, prestriate, or superior temporal sulcus lesions, and normal controls, differed significantly in their ability to shift attention. Analyses of inferred stages in attention shift showed that different processes were disturbed in the three lesion groups. Results are discussed in terms of cortical substrates for "looking" and "seeing".

Animals↗
PubMed1992

Influence of soil water on the physiological and morphological components of plant water balance in Populus trichocarpa, Populus deltoides and their F(1) hybrids.

Patterns of leaf growth, transpiration and whole-plant water balance in Populus trichocarpa, P. deltoides and their F(1) hybrids were studied during a soil drying cycle. Plant responses were analyzed during three distinct stages of dehydration. In stage I, the transpiration rate of drought-stressed plants remained constant and equal to that of well-watered plants even though soil water content declined by more than 40%. Stage II began as soil and plant water deficits induced stomatal closure. When soil water was expressed as a fraction of transpirable soil water, the transition from stage I to stage II occurred at soil water fractions of 0.35, 0.45 and 0.60 for P. trichocarpa, P. deltoides and their F(1) hybrids, respectively. Reductions in leaf growth coincided with the shift from stage I to stage II. As soil water declined further, decreases in relative transpiration and whole-plant leaf area were significantly greater in parental species than in F(1) hybrids. Inherent feedbacks controlling stomatal water loss and the maintenance and growth of leaf tissue appeared to differ between F(1) and parental genotypes in a pattern characteristic of an overdominant mode of inheritance.Stage III began once the ability of stomata to compensate for water loss had been exhausted. Substantial differences were found in plant survival during stage III, with F(1) hybrids surviving longer than parental species. Survival was more strongly correlated with the hydraulic conductivity of xylem tissues than with the dehydration tolerance of leaf tissues. Collectively, these responses suggest that F(1) hybrids were more drought resistant than either parental species and highlight the importance of whole-plant studies of functional relationships between plant growth, water balance and hydraulic conductivity.

Journal Article↗
PubMed1999

Light-dependent suppression of the vestibulo-ocular reflex during development.

In the fish Oreochromis mossambicus, light conditions affect the development of the roll-induced vestibuloocular reflex (rVOR). During development under continous light-dark conditions the rVOR amplitude, which is the maximum eye movement during a complete 360 degrees lateral roll, shows a secondary drop after a first peak at stage 17 by 64% (36.3 degrees at stage 17; 13.0 degrees at stage 20). This drop was shifted by 2 stages to older postembryonal stages and was 33% (29.2 degrees at stage 20; 19.5 degrees at stage 22) less pronounced in animals which were exposed to complete darkness for several days. Because the period of rVOR diminution is sensitive to light conditions, it is likely that outgrowing visual projection fibres reorganize the neuronal network underlying visual-vestibular behavior thus transiently suppressing the rVOR.

Animals↗
PubMed1989

[Hemodynamic changes on the course of septic multiorgan failure patients].

The hemodynamic changes on the course of septic multiorgan failure (s-MOF), and the effects of norepinephrine administrated at septic shock state were evaluated in thirteen patients who died of s-MOF in ICU. The course in ICU was divided into following three stages. Stage I was for a few days after admission in ICU. Stage II was severe infected state. Stage III was the terminal state, i.e., a few days before death. Norepinephrine was administrated when conventional catecholamines (dopamine and/or dobutamine) could not maintain the blood pressure level in the shift from stage II to III, and the hemodynamic changes were evaluated before and after the administration. The following results were obtained: 1) Hemodynamic changes: The stage I was characterized as a moderately hyperdynamic state. The stage II exhibited a typical hyperdynamic state distinguished by a decrease in systemic vascular resistance (SVR). The stage III was distinguished as a normodynamic shock state, because of fall of cardiac output within normal control level. 2) Norepinephrine increased cardiac index, heart rate, and right ventricular stroke work index, but mean arterial pressure, stroke index and SVR did not exhibit any change. However, norepinephrine was useful aid to maintain the circulation in hypotensive state, when conventional catecholamines could not maintain blood pressure any more.

Adult↗
PubMed1994

Electroencephalographic activity associated with shifts of visuospatial attention.

The neural processes underlying shifts of visuospatial attention were studied in normal adults by non-invasive recording of brain electrical activity. Event-related evoked potentials (ERPs) were recorded during target detection tasks with targets preceded by central or peripheral directional cues in the visual field, which are hypothesized to provoke voluntary and reflexive shifts of spatial attention. Reaction time to targets varied as a function of cue type and cue-target interval, indicating that the tasks induced shifts of spatial attention across the visual field. Event-related evoked potential recordings showed that central cues elicited negative potential shifts starting 240 ms after cue onset over posterior scalp sites contralateral to the cued visual field, which spread to anterior scalp sites over time. After 500 ms post cue, negative potentials were more negative in right temporal parietal sites regardless of cue direction. Peripheral cues enhanced the N1 component (140-200 ms post cue) over the contralateral hemisphere. Following N1 enhancement, a sustained negative potential shift appeared after 460 ms post cue at posterior scalp sites contralateral to cued field and spread over the temporal and central regions. These results suggest that the neural processes underlying spatial selection are initiated in the posterior region and that other cortical activities are recruited in a serial fashion. Symmetrical early activation of each contralateral hemisphere suggest independent involvement of the hemispheres in the early stages of shifting attention toward the contralateral visual field. A predominant contribution of the right hemisphere to sustained spatial attention was demonstrated in the late stage of cue processing at the right temporal and parietal regions. Different ERP patterns generated by central and peripheral cues support the hypothesis that distinct neural systems are involved in voluntary and reflexive mechanisms of attention shift.

Adult↗
PubMed2003

Adaptive plasticity in ontogenetic niche shifts stabilizes consumer-resource dynamics.

Ontogenetic niche shifts, changes in the diet or habitats of organisms during their ontogeny, are widespread among various animal taxa. Ontogenetic niche shifts introduce stage structure in a population with different stages interacting with different communities and can substantially affect their dynamics. In this article, I use mathematical models to test the hypothesis that adaptive plasticity in the timing of ontogenetic niche shifts has a stabilizing effect on consumer-resource dynamics. Adaptive plasticity allows consumers in one ontogenetic niche to perform an early shift to the next ontogenetic niche if the resource density of the first niche is low. The early shift will reduce predation by the consumer on the scarce resource. On the other hand, adaptive plasticity allows consumers to delay their shift to the next niche if the resource density of the first niche is high. The delayed shift will increase the predation on the abundant resource. As a result, the scarce resource will tend to increase, and the abundant resource will tend to decrease. This causes density-dependent negative feedback in the resource dynamics, which stabilizes the consumer-resource dynamics. To test this hypothesis, I compare three consumer-resource models differing in terms of mechanisms controlling the timing of the ontogenetic niche shift: the fixed-age model assumes that the age at which the ontogenetic niche shift occurs is fixed; the fixed-size model assumes that the size at the shift is fixed; and the adaptive plasticity model assumes that the timing of the shift is such that the individual fitness of the consumer is maximized. I show that only the adaptive plasticity model has a locally stable equilibrium and that the stabilizing effect is due to the density-dependent negative feedback in the resource dynamics. I discuss the ontogenetic niche shifts of lake fish in light of the obtained result.

Adaptation, Biological↗
PubMed1984

Cognitive asymmetries after waking from REM and NONREM sleep: effects of delayed testing and handedness.

The present paper describes two experiments designed to investigate cognitive asymmetry after awakening from REM and NONREM sleep as a function of time after the awakening and handedness. Two groups of 9 right-handed male subjects each participated in the first experiment. Subjects were awakened from REM and NONREM sleep and after 35 min (Group 1), or 75 min (Group 2), tested on a 6-test battery designed to measure cognitive asymmetry. In contrast to our previous findings in subjects tested within 1-2 min after the awakening who showed a significant sleep-stage dependent shift in cognitive asymmetry, the present results did not show significant differences in performance between the two awakening conditions for any of the groups. Two groups of 12 male and 12 female left-handed subjects participated in the second experiment. All subjects were tested within 1-2 min after the awakenings from REM and NONREM sleep on the same 6-test battery as in experiment 1. Also in contrast to our previous findings in right handers, left-handers did not show any consistent shifts in cognitive asymmetry after the awakenings.

Adult↗
PubMed2002

Surgical resection of multifocal non-small cell lung cancer is associated with prolonged survival.

BACKGROUND: Revisions in the international system for the staging of lung cancer, adopted in 1997, assigned the T4 descriptor to separate tumor nodules in the same lobe and the M1 descriptor to tumor nodules in a different lobe. Consequently, these changes shifted the stage of patients with these lesions to stage IIIB or stage IV. The goal of this review was to determine the impact of multifocal non-small cell lung cancer on survival. METHODS: A database analysis of our cardiothoracic surgery tumor registry was performed to identify all patients who underwent surgical resection of non-small cell lung cancer (NSCLC), who were ultimately determined to have pathologically node-negative disease from 1994 to 1999. All pathology reports were individually reviewed. Survival data were collected on each patient from the date of surgery with a mean duration of follow-up of 46.3 months. Kaplan Meier actuarial survival was determined for all patients. RESULTS: Forty-four patients were identified who underwent complete resection of multiple NSCLC tumors. During this same period, 504 patients underwent complete resection of stage I NSCLC tumors. The 3-year actuarial survival for patients with T1/N0/M0 tumors was 79.6%. In comparison with patients with T1/N0/M0 tumors, the 3-year actuarial survival rates of patients with T2/N0/M0 tumors (72.3%, p = 0.056), T4/N0/M0 tumors (66.5%, p = 0.058), and T1 to T2/N0/M1 tumors (63.6%, p = 0.201) were lower. However, these differences did not achieve statistical significance. CONCLUSIONS: Although there was a trend toward decreased survival in patients with multifocal NSCLC compared with patients with stage I NSCLC, this did not achieve statistical significance. Importantly, survival in these subgroups of patients with stage IIIB or stage IV disease (stage determined solely on the basis of multifocal NSCLC) is better than the survival reported in the series that formed the foundation for these staging changes. These data support complete surgical resection of multifocal lung tumors in patients with node-negative NSCLC.

Adenocarcinoma↗
PubMed2000

[Malacoplakia-like reaction in association with colorectal adenocarcinoma].

17 cases of malacoplakia in association with an adenocarcinoma of the colon or rectum are known. In this report we describe a new case of this rare combination. An 83-year-old comatose female patient was admitted in an emergency situation because of an incipient ileus. A carcinoma had been known for months, but the patient had previously rejected any diagnostic or therapeutic measures. A tumor (6 cm in diameter) in the upper rectum was removed. This tumor had caused an obstruction of the lumen and reached the serosa. Histologically, an adenocarcinoma with suppurations in the stroma was staged pT3, G2, pN0 (clinically pT4 because of the perforated colonic wall). PAS- and von-Kossa-positive Michaelis-Gutmann-bodies were found in macrophages. Ultrastructurally, they turned out to be circular shifted early stage calcifications. Any malacoplakia-like lesion in suspicious areas of the colonic wall should be followed up by further diagnostic measures, since it may indicate the presence of an adenocarcinoma.

Adenocarcinoma↗
PubMed2000

Tobacco cessation intervention in a nurse practitioner managed clinic.

Tobacco cessation counseling by health care professionals has been associated with increased tobacco cessation rates. In this study we compare the effectiveness of two smoking cessation approaches administered by nurse practitioners--a stepped care approach (n = 34) and a routine care approach (n = 41), using a pre- and post-test control group study design. Additionally, this study was guided by the "stages of change" construct of the transtheoretical model. Study results indicated that nurse practitioners delivered consistent office-based advice about tobacco use. In addition, nurse practitioner smoking cessation interventions contributed to positive shifts in stage of change for smoking cessation.

Adult↗
PubMed1987

Kindling-like convulsive activities in the isolated ileum of the guinea pig. I. Electrical stimulation.

A kindling-like convulsive activity model produced by subthreshold, iterative electrical stimulation of the isolated male guinea pig ileum is described. In this model, the mechanical activity of the longitudinal muscular fibers of the ileum was systematically quantified in terms of the basic frequency, tonus, amplitude, and transient amplitude increments (A, n spikes/20 min) of "normal" contractions and presence of high-amplitude, paroxysmal, "epileptiform" contractures (B, n spikes/20 min). Changes in these parameters were statistically compared through consecutive stages of the same stimulated male ileum (I = initial activation, II = initial inhibition. IIIA = late activation, and IV = late inhibition) and equivalent stages of stimulated female and nonstimulated male ilea where "kindling-like" activities were only occasionally observed. Basic tonus, amplitude, and number of A spikes showed significant changes through consecutive stimulated male ileum "kindling" stages: increased from baseline to stage I, decreased from I to II, increased from II to III and from III to IIIA, and decreased from IIIA to IV. The number of B spikes significantly increased from II to III, III to IIIA, and IIIA to IV. No significant changes in baseline frequency were found through all stages nor in tonus, amplitude, A and B spikes between stage IV and the self-sustained activity observed 120 min after stimulation. In addition, there were significant correlations between B spikes vs. basic tonus and amplitude and A spikes when the stimulated male ileum shifted from stage II to IIIA (positive correlations) and from IIIA to IV (negative correlations). Basic tonus during stage I, basic amplitude during IIIA, A spikes during self-sustained activity and B spikes during III, IIIA, IV, and self-sustained activity were in the stimulated male ileum larger than those in both the stimulated female and the nonstimulated male ilea. Tonus and A spikes during III and IIIA in the stimulated male ileum were larger than in the nonstimulated, whereas tonus during IV and self-sustaining activity and amplitude during II in the stimulated male ileum were smaller than in the female stimulated ileum.

Animals↗
PubMed1997

Descriptive physiological data on a sleep bruxism population.

We studied 24 bruxers (23-67 years old). They often complained of orofacial and bodily pain and presented autonomic symptoms (sweating 23%, palpitations at night 62%, decreased libido 50%); 19% had increased blood pressure requiring treatment, and 65% reported frequent headaches in the morning. Deep sleep and rapid eye movement (REM) were delayed. An average of 167 orofacial episodes developed during the night. The mean number of masseter bursts strictly defined as bruxism was 79, the mean delay for the first occurrence after sleep onset 18 minutes. The majority of bruxism occurred in stage 2 sleep and REM sleep. The mean number of shifts of sleep stages was 70, one-third occurring within the first minute following a bruxing episode, and 15% of bruxing episodes developed after a shift in sleep stage. Electroencephalogram showed alpha-delta pattern in 15% of the subjects. Short-lasting alpha activity was often encountered during the 10 seconds preceding the development of a bruxing episode. Tachycardia developed at its onset, persisting for 10 seconds. We suggest that, as a minor alarm response to endogenous/exogenous stimuli, arousal develops and is often followed by motor activation, such as a burst of bruxing, with, as in any situation when motor activity suddenly increases, a secondary increase of heart activity.

Adolescent↗
PubMed1999

[Controversies in the new TNM staging system].

The latest revision of the International System for Staging Lung Cancer was published in June 1997. We discuss the following 4 major items in the new TNM staging system. 1) The fact that stage I was divided into stage IA (T1N0M0) and IB (T2N0M0) is reasonable, as the survival prospects for the subsets differ significantly. 2) The fact that stage II was divided into stage IIA (T1N1M0) and IIB (T2N1M0) is not appropriate, However, there is no significant survival difference between the T1N1M0 subset and the T2N1M0 subset, because there are fewer T1N1M0 cases. 3) The fact that the T3N0M0 subset was shifted into stage IIB is reasonable. Patients who undergo resection of tumors invading the parietal pleura, neighboring lobe, and main bronchus within 2 cm of the carina in the T3N0M0 group have a good prognosis, but those who undergo resection of tumors invading the rib, intercostal muscle, and diaphragm in the T3N0M0 group have a poor prognosis. 4) The decision to designate satellite lesions within the lobe of the primary tumor as T4 is controversial, because it is very difficult to determine whether satellite lesions are metastases from other lesions or if they are primary synchronous neoplasms.

Humans↗