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PubMed2001

Asymmetrical hand force persistence and neuroleptic treatment in schizophrenia.

The recent development of an isometric instrument for the precise quantification of hand force persistence has created a novel opportunity for the evaluation of potential motor asymmetries in schizophrenia and their response to treatment. A study of asymmetries in the unmedicated state may provide insight into the pathogenesis of schizophrenia, whereas alterations of asymmetries in response to antipsychotic medication could assist the delineation of a cerebral mechanism for the effects of pharmacotherapy. The hand force persistence of 21 unmedicated patients with schizophrenia was compared to 21 age, gender, and handedness matched normal controls. The effect of neuroleptic treatment on hand force persistence was then evaluated on a subset of 10 patients after at least 30 days of treatment. The anticipated asymmetry was evident in the unmedicated sample that showed impaired right hand force persistence compared to the normal control sample. The prospective comparison showed an alleviation of the asymmetry resulting from an improvement of right hand force persistence with treatment. In addition to providing further support to a primary left hemisphere cerebral involvement in schizophrenia, the present results suggest that prior investigations of motor asymmetry may have been compromised by the study of medicated patients. The apparently paradoxical improvement of motor skill may relate to the substantial number of patients treated with 2nd generation neuroleptic medications which may implicate an improvement in left hemisphere physiology in the cognitive advantages of the novel treatments.

Adult↗
PubMed2003

Formation and extraction of persistent fumigant residues in soils.

Fumigants are commonly thought to be short-lived in soil, but residues have been found in soils years following application. In this study, formation and extraction of persistent soil fumigant residues were investigated. Fumigants 1,3-dichloropropene (1,3-D), chloropicrin (CP), and methyl isothiocyanate (MITC) were spiked into Arlington, Glenelg, and Hagerstown soils and incubated for 30 d under controlled conditions. The incubated soils were evaporated for 20 h prior to extraction with a variety of organic solvents at different temperatures. Extraction with acetonitrile in sealed vials at 80 degrees C for 24 h was the most efficient method to recover persistent soil fumigant residues. At application rates of 1000-1700 mg (kg of soil)(-1), persistent residues of 1,3-D, CP, and MITC in the three soils ranged from 5 to 67 mg kg(-1). The residue content increased with application rate, correlated positively with soil silt content, decreased dramatically as indigenous organic matter (OM) was removed, and changed little with external OM addition. Adsorption to clay surfaces was not important in fumigant retention, while pulverization of soil aggregates significantly decreased persistent fumigant residues. The results suggest that persistent fumigant residues are retained in soil intra-aggregate micropores resulting from binding clay flocs and silt particles by humic substances.

Adsorption↗
PubMed2006

Persistence of Klebsiella pneumoniae on simulated biofilm in a model drinking water system.

Persistence of Klebsiella pneumoniae on corroded iron surfaces in drinking water was studied using biofilm annular reactors operated under oligotrophic conditions. Reactors were inoculated with K. pneumoniae, and persistence was monitored in the bulk and biofilm phases. Initial cell concentration of 10(6) MPN/mL in the bulkwater phase resulted in significantly longer adhesion than initial concentrations 1 and 2 orders of magnitude lower. K. pneumoniae cultured in low nutrient growth medium persisted longer in dechlorinated tap water than those cultured in full strength medium. Cell surface charge was more negative under low nutrient conditions, and this influenced electrostatic attraction between the cells and the oxidized iron surface. Cells grown in full strength media persisted longer in water with both low (<0.2 mg/L) and high (>0.5 mg/L) free chlorine residuals. Growth media injected with the cells dechlorinated the water allowing adhesion without inactivation. Microelectrode measurements showed a 40-70% drop in free chlorine from the bulk to the coupon surface, which decreased disinfectant potency against adhered cells. Growth and injection conditions clearly influenced cell adhesion and persistence, but permanent colonization of the corroded iron surface by K. pneumoniae was not observed.

Biofilms↗
PubMed1998

Hereditary persistence of alpha-fetoprotein. Case report and review of the literature.

Persistently elevated alpha-fetoprotein (AFP) levels of 24 to 30 micrograms/ml (normal < 10 micrograms/ml) were found in a 38-year-old healthy man. Subsequently, AFP was found to be elevated in another five out of 13 family members within three generations. The pedigree is consistent with an autosomal dominant inheritance pattern. No discernible disease and no functional abnormality appears to be associated with this clinically benign disorder which has been recorded in the literature on four occasions to date. The reported AFP levels in these other cases ranged from 18 to 198 micrograms/ml. Physiologically, AFP is mainly produced in the liver and the yolk sac of human fetuses more than four weeks old, with peak values of up to 4 mg/ml at 12 to 16 weeks of gestation. After birth, AFP levels usually fall, within eight to 12 months, to a very low concentration of < 10 micrograms/ml and persist at low levels throughout life. However, AFP levels can rise above normal in both children and adults in distinct conditions and diseases which will be discussed. Hereditary persistence of alpha-fetoprotein (HPAFP) should be considered in both children and adults with unexplained and persistent elevation of AFP e.g., those screened for hepatocellular carcinoma or diagnosed for germ cell tumor. It should also be recognized in AFP screening for neural tube defects or Down's syndrome during pregnancy. Hereditary persistence of AFP can be easily confirmed by analyzing AFP levels in family members.

Adult↗
PubMed2006

Congenital vascular malformations: the persistence of marginal and embryonal veins.

BACKGROUND: In about 18% of cases with conginental vascular malformations we find a perspective of an atypical truncular vein, located along the outside of the leg, frequently extended from the dorsal foot up to the bottom. In presence of a normally developed system of the deep collecting veins of the lower limb and within the pelvic outflow we are talking about a persisting marginal vein (MV). Hypoplasia or even aplasia of the main deep veins in contrary defines the persisting embryonal vein (EV). Already in childhood these truncular dysplastic veins tend to develop varicose enlargement, causing severe reflux of a huge volume of blood--even more when being associated with av-fistulas (46%). In consequence a rapidly growing chronic venous insufficiency will guide to additional injuries. PATIENTS AND RESULTS: We have analysed 97 patients showing a persisting MV (n: 92 ) within a total of 102 legs. A persistent embryonal vein (EV) was seen 10 times within this clientel. The persisting truncular veins, associated with phlebectasias and typical clinical symptoms have been examined in a diagnostic "step-by-step" procedure, mainly phlebographically (ascending leg phlebography and varicography), including direct venous blood pressure measurements (phlebodynamometry) and--if needed--by arteriography, showing av-shunting fistulae in 46% of cases. CT and MRI were consulted for the exact therapy planing (frequently initially offered as a non-invasive, however, inadequate key of diagnostic). Actually now these techniques cannot replace pre-operatively the angiographic imaging techniques. CONCLUSIONS: The analysis of clinical, morphologic and functional signs, guiding to a specific therapy-relevant classification of MV's and EV's will be presented. And a specific strategy of surgical repair, interventional treatment of av-fistulas and conservative compressive follow-up treatment attempting palliative recompensation of the diseased venous outflow will be discussed also.

Adolescent↗
PubMed2000

Hepatocellular proliferation in patients with chronic hepatitis C and persistently normal or abnormal aminotransferase levels.

BACKGROUND/AIMS: Some patients chronically infected with the hepatitis C virus (HCV) have persistently normal alanine aminotransferase (ALT) levels while progressive liver damage is observed histologically. In the present study, we compared the rate of proliferation, apoptosis, and necrosis in liver biopsy specimens of patients with persistently normal or elevated ALT levels. METHODS: Fourteen patients with persistently normal and 14 age- and sex-matched patients with elevated ALT levels were enrolled. Proliferation was detected using anti-Ki 67 in 10-microm liver biopsy specimens of the patients. Apoptosis was measured by TUNEL-assay and by monoclonal anti-M30 directed against caspase-cleaved cytokeratin 18 filaments. RESULTS: The mean number of anti-Ki 67 positive hepatocytes was lower in patients with persistently normal aminotransferases (3.1 +/- 2.8/10(3) vs 10.8 +/- 8.8/10(3) hepatocytes, p<0.0011) and was correlated with serum ALT (r=0.86, p<0.01) and aspartate aminotransferase levels (r=0.83, p<0.01). The rate of apoptosis detected by TUNEL assay was low and not different between patients with persistently normal and elevated aminotransferases. Staining with anti-M30 revealed a granular staining pattern and showed a trend towards higher cell death rates in patients with elevated aminotransferase levels (apoptotic hepatocytes with >75% staining: 3.97 +/- 6.24/10(3) hepatocytes vs 13.65 +/- 19.41/10(3) hepatocytes; p=0.08). CONCLUSIONS: Patients with chronic hepatitis C and normal aminotransferases have significantly lower hepatocyte proliferation rates and show a trend towards lower apoptosis rates compared with patients with elevated aminotransferases.

Adult↗
PubMed2001

Adolescence-limited versus persistent delinquency: extending Moffitt's hypothesis into adulthood.

The authors examined how neuropsychological, personality, and environmental risk factors and their interactions were related to trajectories of delinquent behavior from adolescence to adulthood. Four waves of longitudinal data from 698 male participants, ages 12-18 at Time 1 and ages 25-31 at Time 4, were included in the analyses. Using a growth mixture model approach, 4 trajectories were identified: nondelinquents, adolescence-limited delinquents, adolescence-to-adulthood-persistent delinquents, and escalating delinquents. Five risk factors distinguished escalating from persistent delinquents and 5 also distinguished nondelinquents from the 3 delinquency trajectories. Persistent delinquents scored significantly higher than adolescence-limited delinquents on only one risk factor, disinhibition. Overall, few of the factors that are related to childhood-to-adolescence persistence were associated with persistence in delinquency beyond adolescence.

Adolescent↗
PubMed1986

Postperformance attributions and task persistence among type A and B individuals: a clarification.

We examined task persistence and postperformance attributions by Type As and Bs on tasks that varied in level of difficulty. On the basis of past research, we hypothesized that Type As would be more self-serving than Type Bs in their attributions for success and failure. We also hypothesized that task persistence would differ among Type As and Bs and would be dependent on task difficulty and perceived task diagnosticity. Type As and Bs attempted multiple sets of anagrams that were either easy or difficult. We measured persistence by the number of anagram sets attempted, and, after task performance, we assessed attributions for success and failure. Results supported both hypotheses. Type As took more credit for success than for failure, whereas Type Bs did not provide reliably different attributions for success and failure. Furthermore, Type As persisted longer at the task when it was difficult and when it was viewed as relatively low in information value. Type Bs persisted longer at the task when it was difficult but viewed as relatively high in information value. Results are discussed in the context of current debates regarding the responses of Type As and Bs to performance settings.

Achievement↗
PubMed1981

Effects of spatial-frequency specific adaptation and target duration on visual persistence.

Two experiments investigated the properties of visual persistence as functions of spatial frequency, stimulus duration, and pattern-specific adaptation. In Experiment 1, increasing the duration of high spatial-frequency gratings from 50 to 500 msec decreased the duration of visual persistence produced by that grating to an asymptotic level. However, low-frequency gratings produced a constant estimate of visual persistence independent of presentation time. Also, spatial-frequency specific adaptation reduced the persistence of the high-frequency gratings to this asymptotic level, but the lower frequency persistence estimates already at this level were unaffected (Experiment 2). These findings are related to possible temporal properties of the sustained and transient visual systems.

Figural Aftereffect↗
PubMed1980

Selection from visual persistence by perceptual groups and category membership.

Following Sperling, the nature of the representation of visual information during visual persistence has been investigated by comparing partial-report (PR) and whole-report (WR) estimates of available information. A PR superiority is considered evidence for the representation of the cued stimulus dimension in visual persistence. In general, PR cues based on a physical characteristic produce a PR superiority, but PR cues based on a category distinction give no higher estimates of available information than is obtained with WR. These findings have been used to support an interpretation of visual persistence based upon a storage system metaphor (e.g., iconic memory), whereby a critical characteristic of the stored information is its "literal" precategorical nature. The present experiments explored whether there are reasonable alternative explanations for the fact that only physical PR cues typical produced a PR superiority. Experiments 1 and 2 demonstrate that the effectiveness of physical PR cues depends upon the "goodness' of the perceptual groups defined by the cued dimension. Perceptual grouping within multi-letter displays was varied according to the principles of proximity (Exp. 1) and similarity (Exp. 2), and the results showed greater PR superiorities when the demand characteristics of the cues were compatible with the implied perceptual groups in the displays. Experiments 3 and 4 establish that PR cues based upon a category distinction (letter-digit) produce a PR superiority when both cue onset latency and cue uncertainty are equated across PR and WR conditions. Circular alphanumeric displays were used, and category PR cues and WR cues were either presented in separate trial blocks (Exp. 3) or intermixed at two possible cue delays relative to display onset (-1000 msec or 0 msec). A PR superiority was found in all conditions. In addition, Experiment 5 shows that the magnitude of this category PR superiority decreased systematically with increases in cue delay (-900 msec, -300 msec, +300 msec, and +900 msec), and in Experiment 6, it was found that the PR superiorities for both physical and category cues decrease at comparable rates with increased cue delay. Since perceptual grouping influences the effectiveness of physical PR cues and category PR cues produce a PR superiority under appropriate conditions, the results question the validity of interpretions of visual persistence that imply the existence of a literal, precategorical storage system. It is suggested that a multichannel view of the visual system provides a more adquate theoretical conceptualization of visual persistence.

Discrimination Learning↗
PubMed1990

Effects of decisional control and work orientation on persistence in preventive health behavior.

Examined persistence in the daily use of fluoride mouthrinse among adolescents as a function of an induced-choice manipulation concerning self-management strategies and freedom to participate in the program. Seventh-grade boys and girls from urban and suburban schools were randomly assigned to a series of either high- or low-choice decisional control manipulations; their daily, home use of fluoride was monitored over a 20-week period. In order to ameliorate the relatively lower persistence rates found previously among suburban (vs. urban) students, all students were given self-management and action instructions as per previous studies. Although suburban students still declined in persistence relative to urban students, female students who received high choice persisted at a higher rate than girls who received low choice. Boys, for the most part, were unaffected by the manipulation. In addition, students' self-reported work orientation was also positively associated with persistence.

Adolescent↗
PubMed2004

The relations between persistent poverty and contextual risk and children's behavior in elementary school.

Does persistent adversity over time have effects on children's behavior beyond the effects of intermittent or concurrent adversity? This study examined the relations between school behavior in 5th grade (mean age = 11 years 0 months) and indexes representing persistent poverty and contextual risk. The indexes described 2-year intervals of family adversity. The results showed effects for persistent risk over 2 consecutive intervals for several factors, but only for recent intervals (3rd and 5th grades), and the factors differed for externalizing behavior, internalizing behavior, and academic competence. The 3rd interval of risk added little to the outcomes, and most factors did not show persistence effects. The results highlight the need for caution in expecting and interpreting effects for persistent adversity.

Child↗
PubMed2003

Pretreatment task persistence predicts smoking cessation outcome.

R. Eisenberger's (1992) learned industriousness theory states that individuals display differing degrees of persistence depending on their history of reinforcement for effortful behavior. These differences may influence the development, maintenance, and cessation of addictive behaviors. In cross-sectional studies, E. P. Quinn, T. H. Brandon, and A. L. Copeland (1996) found that cigarette smokers were less persistent than nonsmokers, and R. A. Brown, C. W. Lejuez, C. W. Kahler, and D. R. Strong (2002) found that smokers who had previously abstained for 3 months were more persistent than those who had never quit. The present study extended these findings by using a prospective design. A pretreatment measure of task persistence (mirror tracing) completed by 144 smokers predicted sustained abstinence throughout 12 months of follow-up. Moreover, persistence predicted outcome independent of other significant predictors: gender, nicotine dependence, negative affect, and self-efficacy.

Adolescent↗
PubMed2006

A temporal same-object advantage in the tunnel effect: facilitated change detection for persisting objects.

Meaningful visual experience requires computations that identify objects as the same persisting individuals over time, motion, occlusion, and featural change. This article explores these computations in the tunnel effect: When an object moves behind an occluder, and then an object later emerges following a consistent trajectory, observers irresistibly perceive a persisting object, even when the pre- and postocclusion views contrast featurally. This article introduces a new change detection method for quantifying percepts of the tunnel effect. Observers had to detect color changes in displays where several objects oscillated behind occluders and occasionally changed color. Across comparisons with several types of spatiotemporal gaps, as well as manipulations of occlusion versus implosion, performance was better when objects' kinematics gave the impression of a persisting individual. The results reveal a temporal same-object advantage: better change detection across temporal scene fragments bound into the same persisting object representations. This suggests that persisting objects are the underlying units of visual memory.

Attention↗
PubMedDate not supplied

Persistent, directional motility of cells and cytoplasmic fragments in the absence of microtubules.

Directional cell locomotion is displayed by many cell types both in vivo and in vitro. In many instances, persistency and directionality are imposed by external stimuli such as chemical attractants or substrate properties. Some cell types, such as fibroblasts or leukocytes, are capable of migrating in the absence of known stimuli in a pattern known as persistent random walk, where the direction of movement is maintained for at least one cell diameter before the cell performs a sudden directional change. In many examples of persistent motility, microtubules are believed to have a key role as elements that stabilize or even determine a cell's direction of movement. If disassembled, persistency is reduced or impaired. Despite some reports to the contrary, these and other observations have led to the widely accepted view that microtubules may be the overall organizers of cell geometry, polarity and motile activity. Here we report that rapid, directional locomotion of fish epidermal keratocytes is independent of the presence of microtubules. Moreover, small cytoplasmic fragments derived from the anterior lamella of these cells are capable of locomoting in a pattern indistinguishable from that of intact cells. Since these fragments contain no nucleus, microtubules or centrioles, the persistency-determining component must be sought in some other component(s) of the cytoplasm, possibly the motile machinery of the lamella itself.

Animals↗
PubMedDate not supplied

Cytoimmunotherapy for persistent virus infection reveals a unique clearance pattern from the central nervous system.

The mechanism(s) by which infectious or malignant material is cleared by the host has long been an area of intensive study. We have used the murine model of infection with lymphocytic choriomeningitis virus (LCMV) to look at immune clearance during persistent infection. LCMV was selected because the mouse is its natural host, it easily induces acute or persistent infection in vivo, and the mechanism by which it is cleared in vivo during acute infection is now well understood. Clearance, although associated with several antiviral immune effector mechanisms, is primarily dependent on the activity of virus-specific cytotoxic T lymphocytes (CTL) restricted by H-2 molecules of the mouse major histocompatibility complex (MHC). If these cells fail to generate or are depleted, progression from acute to persistent infection occurs. Here, using molecular probes, we show that viral nucleic acid sequences, viral proteins and infectious materials can be efficiently and effectively cleared by adoptive transfer of antiviral H-2-restricted lymphocytes bearing the Lyt 2+ phenotype. Viral materials are cleared from a wide variety of tissues and organs where they normally lodge during persistent infection. Unexpectedly, the mode by which viral materials are removed from the central nervous system (CNS) differed markedly from the mechanism of clearance occurring at other sites. These observations indicate the possible use of adoptive lymphocyte therapy for treatment of persistent infections and suggest that immune clearance of products from the CNS probably occurs by a process distinct from those in other organs.

Animals↗
PubMed1993

Virus persistence in acutely infected immunocompetent mice by exhaustion of antiviral cytotoxic effector T cells.

Viruses that are non- or poorly cytopathic have developed various strategies to avoid elimination by the immune system and to persist in the host. Acute infection of adult mice with the noncytopathic lymphocytic choriomeningitis virus (LCMV) normally induces a protective cytotoxic T-cell response that also causes immunopathology. But some LCMV strains (such as DOCILE (LCMV-D) or Cl-13 Armstrong (Cl-13)) derived from virus carrier mice tend to persist after acute infection of adult mice without causing lethal immunopathological disease. Tendency to persist correlates with tropism, rapidity of virus spread and virus mutations. We report here that these LCMV isolates may persist because they induce most of the specific antiviral CD8+ cytotoxic T cells so completely that they all disappear within a few days and therefore neither eliminate the virus nor cause lethal immunopathology. The results illustrate that partially and sequentially induced (protective) immunity or complete exhaustion of T-cell immunity (high zone tolerance) are quantitatively different points on the scale of immunity; some viruses exploit the latter possibility to persist in an immunocompetent host.

Animals↗
PubMed2003

Characteristics of women with persistent thinness.

OBJECTIVE: Western society has become increasingly obesogenic. Despite this trend, some individuals maintain low weights throughout their lives. Little is known about the characteristics of persistently thin individuals. This study examined demographic, health, and psychiatric characteristics of women who reported having been persistently thin throughout childhood, adolescence, and adulthood. RESEARCH METHODS AND PROCEDURES: Participants were 1022 female members of a population-based twin registry. Participants completed a mail survey that included questions regarding demographics, body size in childhood, adolescence, and adulthood, health behaviors and satisfaction, disordered eating, perfectionism, and personality. In previous interview waves, participants completed diagnostic interviews assessing psychiatric and substance use disorders. RESULTS: Persistent thinness was associated with a significantly later age at menarche, lower rates of dieting and binge eating, greater health satisfaction, higher self-esteem, and lower perfectionism and body dissatisfaction. DISCUSSION: Persistent thinness appears to be associated with greater well-being in the present and a later age of menarche in the past. Whether later menarche is causally related to thinness or whether later menarche, persistent thinness, and enhanced well-being all result from a third unmeasured variable such as high sports participation is yet to be resolved.

Adult↗