julilili42/papers huggingface dataset:
The subcortical anatomy of human spatial neglect: putamen, caudate nucleus and pulvinar
2002-02-01

Various studies have documented that right hemispheric lesions restricted to the basal ganglia or to the thalamus may evoke spatial neglect. However, for methodological reasons, the exact anatomical correlate of spatial neglect within these two subcortical structures still remained uncertain. The present study identified these locations by comparing the anatomy of subcortical lesions to the basal ganglia or thalamus between neglect and control patients. Analysis revealed that the putamen, the pulvinar and, to a smaller degree, the caudate nucleus are the subcortical structures typically associated with spatial neglect in humans. All these structures have direct anatomical connections to the superior temporal gyrus (STG), which recently has been identified as the neural correlate of spatial neglect in the human cortex. Therefore, it is assumed that the right putamen, caudate nucleus, pulvinar and STG form a coherent corticosubcortical anatomical network in the genesis of spatial neglect in humans.
A Theory of Prostitution
2002-02-01

Prostitution is low-skill, labor intensive, female, and well paid. This paper proposes a marriage market explanation to this puzzle. If a prostitute compromises her marriage market prospects, she will have to be compensated for forgone marriage market opportunities. We discuss the link between poverty and prostitution and show that prostitution may decrease with male income if wives and prostitutes are drawn from the same pool of women. We point to the role of male sex ratios, and males in transit, in sustaining high levels of prostitution, and we discuss possible reasons for its low reputation and implications for marriage patterns.
Inhibitory control of acquired motor programmes in the human brain
2002-02-01

An important basis of skilled human behaviour is the appropriate retrieval of acquired and memorized motor programmes ('motor memory traces'). Appropriate retrieval is warranted if motor programmes are only activated if necessary and are, probably more often, inhibited if required by the context of a given situation. It is unknown how this type of inhibition is accomplished in the brain. We studied context-dependent modulation of motor memory traces in 18 volunteers and six patients with focal dystonia. Cortical function was assessed with transcranial magnetic stimulation over the primary motor cortex (M1) and with task-related analysis of oscillatory EEG activity. An activation (ACT) and inhibition (INH) condition were compared. In both, visual cues were presented at 1/s. In ACT, subjects had to respond to these cues with individual finger movements as learned in a preceding training session. In INH, subjects had to observe the cues without retrieval of motor responses. During INH, inhibitory control of the motor memory trace was confirmed by significant amplitude reduction of motor evoked potentials (MEPs) compared with baseline. This was accompanied by a significant increase of 11-13 Hz oscillatory activity over the sensorimotor areas during INH. During active retrieval of the motor memory traces, the reverse was true (increased MEP amplitudes, decreased oscillatory 11-13 Hz activity). In a small sample of dystonic patients (n = 6), the increase of 11-13 Hz oscillatory activity during INH was consistently absent. The present data demonstrate for the first time cortical correlates of appropriate, context-dependent inhibition of motor memory traces. We propose that focal increases of oscillatory activity are instrumental for inhibitory control at the cortical level. This concept is supported by the preliminary observations in dystonic patients who are known to have deficits of inhibitory motor control and in whom these context-dependent focal increases of oscillatory activity were absent.
The Ability of Root ZX Apex Locator to Reduce the Frequency of Overestimated Radiographic Working length
2002-02-01

The aim of this in vitro study was to evaluate the ability of the Root ZX device to avoid instrumentation beyond the apical foramen in premolars after conventional working length radiography. Thirty extracted premolars with 43 root canals were subjected to radiographic and electronic working length determination. Radiographic working length determination resulted in overestimation in 51% of the root canals, although the measuring file tip was located to be 0 to 2 mm short of the radiographic apex. Electronic working length measurements with the Root ZX reduced the percentage of overestimation to 21%. In 6 root canals (14%), both radiographic and electronic working length measurements led to overestimation. It is concluded that complementing radiographic working length determination with electronic apex locator measurements may help to avoid overestimation beyond the apical foramen in premolars.
A Single, Bi-functional Aquaglyceroporin in Blood-stagePlasmodium falciparum Malaria Parasites
2002-02-01

The malaria parasite Plasmodium falciparum faces drastic osmotic changes during kidney passages and is engaged in the massive biosynthesis of glycerolipids during its development in the blood-stage. We identified a single aquaglyceroporin (PfAQP) in the nearly finished genome of P. falciparum with highest similarity to the Escherichia coli glycerol facilitator (50.4%), but both canonical Asn-Pro-Ala (NPA) motifs in the pore region are changed to Asn-Leu-Ala (NLA) and Asn-Pro-Ser (NPS), respectively. Expression in Xenopus oocytes renders them highly permeable for both water and glycerol. Sugar alcohols up to five carbons and urea pass the pore. Mutation analyses of the NLA/NPS motifs showed their structural importance, but the symmetrical pore properties were maintained. PfAQP is expressed in blood-stage parasites throughout the development from rings via trophozoites to schizonts and is localized to the parasite but not to the erythrocyte cytoplasm or membrane. Its unique bi-functionality indicates functions in the protection from osmotic stress and efficiently provides access to the serum glycerol pool for the use in ATP generation and primarily in the phospholipid synthesis.
Interaction between Arabidopsis heat shock transcription factor 1 and 70 kDa heat shock proteins
2002-02-01

The activity of the Arabidopsis heat shock transcription factor (HSF) is repressed at normal conditions but activated by cellular stresses. Circumstantial evidence suggests that HSP70 may function as a negative feedback regulator of HSF activity. Here the interaction between HSF and HSP70 is reported using electrophoretic mobility shift and yeast two-hybrid assays. Subdomain mapping indicates an interaction of the activation domain and DNA-binding domain of HSF1 with HSP70.
Is there a Mind? Electrophysiology of Unconscious Patients
2002-02-01

Event related brain potentials (ERPs) provide information about cortical processing in severe neurological patients whose cognitive abilities cannot be expressed in their behavior. In coma, ERPs contribute to the prediction of the outcome. In a vegetative state, ERPs uncover the functional state of cortical processes. The significance of ERPs in the neurophysiological study of consciousness is discussed.
Identification of the Periplasmic Cobalamin-Binding Protein BtuF ofEscherichia coli
2002-02-01

ABSTRACT Cells of Escherichia coli take up vitamin B 12 (cyano-cobalamin [CN-Cbl]) and iron chelates by use of sequential active transport processes. Transport of CN-Cbl across the outer membrane and its accumulation in the periplasm is mediated by the TonB-dependent transporter BtuB. Transport across the cytoplasmic membrane (CM) requires the BtuC and BtuD proteins, which are most related in sequence to the transmembrane and ATP-binding cassette proteins of periplasmic permeases for iron-siderophore transport. Unlike the genetic organization of most periplasmic permeases, a candidate gene for a periplasmic Cbl-binding protein is not linked to the btuCED operon. The open reading frame termed yadT in the E. coli genomic sequence is related in sequence to the periplasmic binding proteins for iron-siderophore complexes and was previously implicated in CN-Cbl uptake in Salmonella . The E. coli yadT product, renamed BtuF, is shown here to participate in CN-Cbl uptake. BtuF protein, expressed with a C-terminal His 6 tag, was shown to be translocated to the periplasm concomitant with removal of a signal sequence. CN-Cbl-binding assays using radiolabeled substrate or isothermal titration calorimetry showed that purified BtuF binds CN-Cbl with a binding constant of around 15 nM. A null mutation in btuF , but not in the flanking genes pfs and yadS , strongly decreased CN-Cbl utilization and transport into the cytoplasm. The growth response to CN-Cbl of the btuF mutant was much stronger than the slight impairment previously described for btuC , btuD , or btuF mutants. Hence, null mutations in btuC and btuD were constructed and revealed that the btuC mutant had a strong impairment similar to that of the btuF mutant, whereas the btuD defect was less pronounced. All mutants with defective transport across the CM gave rise to frequent suppressor variants which were able to respond at lower levels of CN-Cbl but were still defective in transport across the CM. These results finally establish the identity of the periplasmic binding protein for Cbl uptake, which is one of few cases where the components of a periplasmic permease are genetically separated.
Evaluation of Use of Epstein-Barr Viral Load in Patients after Allogeneic Stem Cell Transplantation To Diagnose and Monitor Posttransplant Lymphoproliferative Disease
2002-02-01

ABSTRACT Epstein-Barr virus (EBV)-induced posttransplant lymphoproliferative disease (PTLD) continues to be a serious complication following transplantation. The aim of the present study was to evaluate the EBV load as a parameter for the prediction and monitoring of PTLD. The EBV load was analyzed by a quantitative competitive PCR with 417 whole-blood samples of 59 patients after allogeneic stem cell transplantation (SCT). The EBV load was positive for all 9 patients with PTLD and for 17 patients without PTLD. The viral loads of patients with manifest PTLD differed from the loads of those without PTLD (median loads, 1.4 × 10 6 versus 4 × 10 4 copies/μg of DNA; P &lt; 0.0001). A threshold value of 10 5 copies/μg of DNA showed the best diagnostic efficacy (sensitivity, 87%; specificity, 91%). However, in patients with less than three major risk factors for PTLD, the positive predictive value of this threshold was rather low. One week prior to the manifestation of PTLD, the EBV load was as low in patients who developed PTLD as in patients without disease (median, 2.2 × 10 4 copies/μg of DNA; P was not significant). EBV DNA tested positive first at 20 to 71 days prior to the clinical manifestation of PTLD and occurred with the same delay after transplantation regardless of disease (median delay, 52 versus 63 days; P was not significant). EBV DNA was detected earlier in patients with primary infections than in those with reactivations (33 versus 79 days; P = 0.01), but the peak levels were similar in the two groups. EBV primary infection or EBV reactivation is frequent in patients after allogeneic SCT but results in PTLD only in a subgroup of patients. Although evaluation of the EBV load has limitations, the EBV load represents a valuable parameter to guide therapy.
Salter Innominate Osteotomy for the Treatment of Developmental Dysplasia of the Hip in Children
2002-02-01

When an acetabulum can be most closely restored to a normal configuration without the development of avascular necrosis, good long-term results (lasting for more than thirty years) can be expected. When open reduction is necessary, it is preferable to perform it separately prior to the Salter innominate osteotomy. The grade of dislocation at the time of the first examination and immediately preoperatively, the grade of avascular necrosis of the femoral head, and the adequacy of surgical correction are important prognostic factors for the long-term clinical result.
Chronic Exposure to a GSM-like Signal (Mobile Phone) Does Not Stimulate the Development of DMBA-Induced Mammary Tumors in Rats: Results of Three Consecutive Studies
2002-02-01

Certain epidemiological and experimental studies raised concerns about the safety of radiofrequency (RF) electromagnetic fields because of a possible increased risk of leukemia and lymphoma. In this study, an RF field used in mobile telecommunication was tested using 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumors in female Sprague-Dawley rats as a model for human breast cancer. Three experiments were carried out under strictly standardized conditions and were started on the same day of three consecutive years. The field consisted of a GSM-like signal (900 MHz pulsed at 217 Hz, pulse width 577 micros) of relatively low power flux density (100 microW/cm(2) +/- 3 dB) and was applied continuously throughout each experiment to freely moving animals. The specific absorption rates averaged over the whole body were 17.5-70 mW/kg. The highest values in young animals were at or around the exposure limit permissible for the general public (i.e. 80 mW/kg). The animals were palpated weekly for the presence of mammary tumors and were killed humanely when tumors reached a diameter of 1-2 cm to allow a reliable histopathological classification and a distinction between malignant and benign subtypes. The overall results of the three studies are that there was no statistically significant effect of RF-field exposure on tumor latency and that the cumulative tumor incidence at the end of the experiment was unaffected as well. The risk ratios were 1.08 (95% CI: 0.91-1.29) and 0.96 (95% CI: 0.85-1.07) for benign and malignant tumors, respectively. These observations are in agreement with other published findings. In the first experiment, however, the median latency for the development of the first malignant tumor in each animal was statistically significantly extended for RF-field-exposed animals compared to controls (278 days compared to 145 days, P = 0.009). No such differences were detected in the two subsequent experiments. These results show that low-level RF radiation does not appear to possess carcinogenic or cancer-promoting effects on DMBA-induced mammary tumors. To explain the mechanisms underlying the different results obtained in the three experiments, a hypothesis is presented which is based upon the neuroendocrine control mechanisms involved in the promotion of DMBA-induced mammary tumors. Despite the apparent absence of stimulatory effects of low-level RF-field exposure on the development and growth of solid tumors, it will be necessary to verify these results for leukemias and lymphomas, which may have completely different biological control mechanisms.
Dose‐dependent rescue of axotomized rat retinal ganglion cells by adenovirus‐mediated expression of glial cell‐line derived neurotrophic factorin vivo
2002-02-01

Abstract Adult rat retinal ganglion cells undergo degeneration after optic nerve transection. Repeated intraocular injection of glial cell‐line derived neurotrophic factor (GDNF) has been shown to be efficient in enhancing retinal ganglion cell survival following optic nerve axotomy. In the present study we evaluated the potential survival‐promoting effect of adenovirally administered GDNF on axotomized retinal ganglion cells. A single intravitreal injection [7 × 10 7 plaque‐forming units (pfu) or 7 × 10 8 pfu] of an adenoviral vector expressing the rat GDNF gene from a cytomegalovirus promoter enhanced retinal ganglion cell survival 14 days after axotomy by 67 and 125%, respectively, when compared to control animals. Intraocular administration of the vector rescued 12.6 and 23%, respectively, of the retinal ganglion cells which would otherwise have died after axotomy. An increase in retinal GDNF protein and specific virally transduced GDNF mRNA expression was detected following intraocular vector application. Our data support previous findings showing that adenoviral delivery of neurotrophic factors to the vitreous body is a feasible approach for the prevention of axotomy‐induced retinal ganglion cell death in vivo and may constitute a relevant strategy for future treatment in traumatic brain injury and ensuing neurodegeneration.
TWO-COMPONENT DRESSED-BAG MODEL FOR NN INTERACTION: DEUTERON STRUCTURE AND PHASE SHIFTS UP TO 1 GeV
2002-02-01

A two-component model is developed for the intermediate-range NN interaction based on a new mechanism with an intermediate symmetric six-quark bag "dressed" by σ and other fields. To calculate the transition amplitude, the microscopic six-quark shell-model in combination with the 3 P 0 -quark pion production mechanism is used. As a result, an effective energy-dependent NN interaction is constructed. The new quark–meson model for the NN interaction has been demonstrated to result in a new type of NN tensor force at intermediate ranges, which is crucially important for the treatment of tensor mixing at intermediate energies. The suggested model is able to describe NN phase shifts in a broad energy range from low energy up to 1 GeV, and the deuteron structure. The generalization of the model results in new spin-orbit 2N and 3N forces and new meson-exchange currents induced by intermediate dressed bag components, and also in the enhancement of a collective σ-field in nuclei.
Specific role for cathepsin S in the generation of antigenic peptidesin vivo
2002-02-01

To address the role of different proteases in degradation of antigen destined for MHC class II-restricted presentation, we generated cathepsin-deficient mice carrying a transgenic B cell receptor (BCR) specific for hen egg lysozyme (HEL). We demonstrate that degradation of HEL in B lymphocytes is highly processive and does not result in discrete processing intermediates. Moreover, degradation of HEL does not require initial unlocking of the antigen by any of the cathepsins tested. Using mass spectrometry and microsequencing, we show that all major cathepsins (CatS, CatL, CatB, and CatD) digest HEL in vitro with considerable redundancy, although some preferential cleavages are evident. These observations have a functional correlate: when triggered by cathepsin S-deficient antigen-presenting cells, T cells that recognize different HEL epitopes fail to present two HEL-derived epitopes, while a third epitope is presented independently of the activity of cysteine proteases. We conclude that the proteolytic processing machinery is redundant, and that several proteases can substitute for each other to degrade a given antigen. However, a certain degree of proteolytic specificity is demonstrable for the generation of particular epitopes, notably by CatS.
Relationships Among Age, Proinsulin Conversion, and β-Cell Function in Nondiabetic Humans
2002-02-01

The aim of the present study was to examine the relationships among β-cell function, proinsulin conversion to insulin, and age. We studied insulin and proinsulin secretion in nondiabetic subjects during an oral glucose tolerance test (OGTT) using published indexes of β-cell function (n = 379, age 16–68 years) and a modified hyperglycemic clamp (10 mmol/l, additional glucagon-like peptide [GLP-1] infusion, final arginine bolus; n = 50, age 19–68 years). Proinsulin conversion to insulin was assessed using proinsulin/insulin (PI/I) ratios immediately after an acute stimulus (OGTT, 30 min; hyperglycemic clamp, 2.5–5.0 min after glucose and arginine). There was a negative correlation between age and β-cell function (adjusted for insulin sensitivity, BMI, and fasting glucose) in the OGTT (r = −0.21, P &amp;lt; 0.001) and first phase of the hyperglycemic clamp (r = −0.30, P = 0.03), but not second phase (r = −0.08, P = 0.6) or arginine-induced insulin secretion (r = 0.06, P = 0.7). There was a positive correlation between age and the PI/I ratio in the OGTT (r = 0.24, P &amp;lt; 0.001). Analogously, there was also a positive correlation between age and the PI/I ratio during first phase (r = 0.37, P = 0.009) and arginine stimulation (r = 0.33, P = 0.01) of the hyperglycemic clamp. First-phase insulin secretion of the hyperglycemic clamp was inversely correlated with the PI/I ratio (r = −0.60, P &amp;lt; 0.001). Interestingly, adjusting first-phase secretion rate for the PI/I ratio abolished the linear relationship with age (r = −0.06, P = 0.7). In conclusion, aging is associated with deteriorating β-cell function and deteriorating proinsulin conversion to insulin. The age effect on insulin secretion appears to be attributable at least in part to an impairment of proinsulin conversion to insulin.
Vitality status of microorganisms in infected human root dentine
2002-02-01

Abstract Aim This experimental study was initiated to establish a method for characterizing the vitality status of bacteria in infected human root dentine by differentiating between viable and dead microorganisms. Methodology Twenty‐four root segments of extracted human teeth were infected with either Streptococcus sanguinis or Enterococcus faecalis for 8 weeks. Baseline samples from root dentine (rd) were collected after 4 weeks. These were compared with samples taken at week 8 (control group: n = 12) and with samples collected at week 12 after calcium hydroxide treatment for four weeks (test group: n = 12). After marking viable and dead bacterial cells by two fluorescent dyes, the portion of viable bacteria (PVB) was determined, as well as the number of colony‐forming units (CFU). Results Viable and dead bacteria were identified in all ‘rd’ samples. PVB rd values were lower than PVB values of the bacterial suspension in the root canal lumen. In the control group, PVB rd and CFU rd did not markedly differ at week 4 and at week 8, regardless of the strain used. In the test group, viable but non‐culturable sanguinis streptococci (mean PVB rd = 27%; CFU rd = 0) were detected, despite calcium hydroxide treatment. The viability of E. faecalis was not affected by calcium hydroxide. Conclusions Fluorescence labelling of bacteria in human root dentine gives valuable additional information about their vitality status compared to the parameter CFU. The method may be suitable for following the fate of bacteria in dentinal tubules, for example in the presence of intracanal dressings.