bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of T‐Cell Receptor Beta Chain Variable Gene Segment Usage in Healthy Adult Responders and Nonresponders to Recombinant Hepatitis B Vaccine
Authors: Soroosh P. , Shokri F. , Azizi M. , Jeddi‐Tehrani M. 
Published: May 2003

AbstractOne to 10 per cent of healthy adult individuals do not produce protective levels of anti‐hepatitis B surface (HBs) antibodies, following a standard vaccination protocol. Hole in HBs antigen (Ag)‐specific T‐cell repertoire is amongst the possible defects, which may lead to humoral unresponsiveness and is the main objective of this study. We analysed TcR BV (T‐cell receptor beta chain variable) gene usage in T lymphocytes from nine healthy adult responders and six nonresponders to recombinant HB vaccine, before and after booster vaccination. CD4+ and CD8+ T‐cell populations were isolated from peripheral blood mononuclear cells by magnetic beads, and the expression of TcR BV genes in each population was investigated by reverse transcription polymerase chain reaction and hybridization with specific probe. When the usage of each TcR BV gene within CD4+ and CD8+ T cells of the responders was compared with that of nonresponders, statistically significant difference (P < 0.01) was noted for BV5S2‐3 gene family in CD4+ T cells of nonresponders. Furthermore, individual vaccinees were shown to overexpress several TcR BV genes. To characterize the T‐cell repertoire and determine their clonal nature, analysis of CDR3 length polymorphism was performed. Our results show that T‐cell response to HBsAg is generally oligoclonal and involves multiple BV families. Furthermore, overexpressed individual TcR BV genes and CDR3 length distributions in response to HBsAg are subject‐dependent. In conclusion, our results are not in line with the notion that defective TcR repertoire may be an explanation for unresponsiveness to recombinant HBsAg vaccine.
The Possibility of B‐Cell‐Dependent T‐Cell Development
Authors: Keshavarzi S. , Rietz C. , Simões S. , Shih S. , Platt J. L. , Wong J. , Wabl M. , Cascalho M. 
Published: May 2003

AbstractThe development of T cells is thought to be independent of B cells. However, defects in cell‐mediated immunity in individuals with B‐cell deficiency suggest the contrary. To test whether B cells affect T‐lymphocyte development, we constructed mice with a monoclonal T‐cell compartment (MT) and monoclonal B‐ and T‐cell compartments (MBTs). In these mice, the T cells expressed a DO 11.10 transgenic (DO‐T) cell receptor restricted to major histocompatibility complex (MHC) class IId. While CD4+ DO‐T lymphocytes are rare in transgenic H‐2b MT mice, we found that in H‐2b MBT mice under the influence of B cells, DO‐T lymphocytes mature into large numbers of CD4+ peripheral T cells. H‐2b MBT mice have more CD4+ thymocytes than H‐2b MT mice. These data are consistent with the view that B cells play some role in thymocyte development.
T‐Cell Receptor Excisional Circles, Telomere Length, Proliferation and Apoptosis in Peripheral Blood Mononuclear Cells of Human Immunodeficiency Virus‐Infected Individuals after 18 Months of Treatment Induced Viral Suppression
Authors: Aladdin H. , Katzenstein T. , Dreves A.‐M , Ryder L. , Gerstoft J. , Skinhøj P. , Pedersen B. K. , Ullum H. 
Published: May 2003

AbstractThis study evaluated the effect of highly active antiretroviral therapy (HAART)‐induced viral suppression on T‐cell receptor excisional circles (TRECs), telomere length, proliferative responses and spontaneous as well as phytohaemagglutinin (PHA)‐stimulated lymphocyte apoptosis in 27 human immunodeficiency virus (HIV)‐infected individuals followed for 18 months during HAART. Our results show that HAART significantly increased the level of TRECs in CD4+ cells (P = 0.003) after 18 months of almost continuously suppressed HIV‐RNA levels. Lymphocyte proliferative responses and apoptosis levels in patients were significantly lower and significantly higher, respectively, compared with healthy controls. The proliferative response and apoptosis levels did not change during follow up. Changes in telomere length were observed in CD4+ and in CD8+ T cells. The study demonstrated that HAART induces normal TREC levels in the CD4+ T‐cell pool. However, the other perturbed functions in T cells indicate that immune reconstitution is incomplete and may need longer viral suppression.
Increased Brain‐Derived Neurotrophic Factor Expression in White Blood Cells of Relapsing–Remitting Multiple Sclerosis Patients
Authors: Gielen A. , Khademi M. , Muhallab S. , Olsson T. , Piehl F. 
Published: May 2003

AbstractCentral nervous system (CNS)‐autoreactive immune responses can exert neuroprotective effects, possibly mediated via the release of neurotrophic factors from infiltrating leucocytes. Herein, we analysed neurotrophin and cytokine mRNA levels using TaqMan polymerase chain reaction in unstimulated peripheral blood mononuclear cells (PBMCs) from multiple sclerosis (MS) patients in remission and controls. We demonstrate that mRNA for brain‐derived neurotrophic factor (BDNF), but not neurotrophin‐3 or nerve growth factor (NGF), is readily detectable in PBMC and that levels in MS are increased by approximately 60% compared with patients with other neurological diseases or healthy subjects. These results provide additional evidence that a potentially neuroprotective facet of autoimmune inflammation is present in MS.
A unique variant of streptococcal group O‐antigen (C‐polysaccharide) that lacks phosphocholine
Authors: Bergström Niklas , Jansson Per‐Erik , Kilian Mogens , Skov Sørensen Uffe B. 
Published: May 2003

Streptococcus mitis strain SK598, which represents a subgroup of biovar 1, possesses a unique variant of the C‐polysaccharide found in the cell wall of all strains of Streptococcus pneumoniae and in some strains of S. mitis. This new variant lacks the choline methyl groups in contrast to the previously characterized forms of C‐polysaccharide, which all contain one or two choline residues per repeat. The following structure of the repeating unit of the SK598 polysaccharide was established: where AAT is 2‐acetamido‐4‐amino‐2,4,6‐trideoxy‐d‐galactose.This structure is identical to the double choline‐substituted form of C‐polysaccharide, except that it is substituted with ethanolamine instead of choline. This extends the number of recognized C‐polysaccharide variants to four.
Studies on structure–function relationships of indolepyruvate decarboxylase from Enterobacter cloacae, a key enzyme of the indole acetic acid pathway
Authors: Schütz Anja , Golbik Ralph , Tittmann Kai , Svergun Dmitri I. , Koch Michel H. J. , Hübner Gerhard , König Stephan 
Published: May 2003

Enterobacter cloacae, isolated from the rhizosphere of cucumbers, produces large amounts of indole‐3‐acetic acid. Indolepyruvate decarboxylase, the key enzyme in the biosynthetic pathway of indole‐3‐acetic acid, catalyses the formation of indole‐3‐acetaldehyde and carbon dioxide from indole‐3‐pyruvic acid. The enzyme requires the cofactors thiamine diphosphate and magnesium ions for catalytic activity. Recombinant indolepyruvate decarboxylase was purified from the host Escherichia coli strain JM109. Specificity of the enzyme for the substrates indole‐3‐pyruvic acid, pyruvic acid, benzoylformic acid, and seven benzoylformic acid analogues was investigated using a continuous optical assay. Stopped‐flow kinetic data showed no indication for substrate activation in the decarboxylation reaction of indole‐3‐pyruvic acid, pyruvic acid or benzoylformic acid. Size exclusion chromatography and small angle X‐ray solution scattering experiments suggested the tetramer as the catalytically active state and a pH‐dependent subunit association equilibrium. Analysis of the kinetic constants of the benzoylformic acid analogues according to Hansch et al. [Hansch, C., Leo, A., Unger, S.H., Kim, K.H., Nikaitani, D & Lien, E.J. (1973) J. Med. Chem.16, 1207–1216] and comparison with indole‐3‐pyruvic acid conversion by pyruvate decarboxylases from Saccharomyces cerevisiae and Zymomonas mobilis provided some insight into the catalytic mechanism of indolepyruvate decarboxylase.
Female Baboons’ Responses to Male Loud Calls
Authors: Kitchen Dawn M. , Cheney Dorothy L. , Seyfarth Robert M. 
Published: May 2003

AbstractMale baboons (Papio cynocephalus ursinus) give loud, two‐syllable ‘wahoo’ calls in response to predators (alarm wahoos) and during aggressive displays that may include multiple males chasing each other or females (contest wahoos). Although acoustic analysis has revealed significant differences between the two calls, these differences are subtle and the two subtypes can be difficult for humans to distinguish. Whatever the evolutionary mechanisms that might have acted on the production of acoustically graded loud calls, it would seem to be adaptive for listeners to discriminate among calls that are given in qualitatively different contexts. This is particularly true in the case of female baboons. Alarm wahoos, which are given during predator encounters, demand qualitatively different responses from contest wahoos, which are given in contexts when females are at risk of harassment and infanticide by males. In playback experiments, females responded for significantly longer durations to alarm than to contest wahoos. Moreover, only alarm wahoos caused females to flee. Despite their acoustic similarity, female baboons appear to associate alarm and contest wahoos with qualitatively different events.
Testing an Adaptive Hypothesis Through Context‐Dependence: Effects of Water Depth on Foraging Behaviour in Three Species of Garter Snakes
Authors: de Queiroz Alan 
Published: May 2003

AbstractAdaptive hypotheses based on interspecific comparisons can be tested by evaluating the context‐dependence of the behaviour of individual organisms. Drummond (Behaviour, 86, 1983, 1) categorized garter snake species (Thamnophis) as terrestrial–aquatic generalists or aquatic specialists based on diet and aquatic foraging behaviour. He hypothesized that the characteristic foraging behaviours of aquatic specialists – including frequent crawling on the underwater substrate and a high rate of underwater predatory strikes – are adaptations for feeding on relatively widely dispersed aquatic prey. Drummond's hypothesis based on interspecific comparisons suggests that individual snakes might change their foraging in the direction of aquatic specialist behaviour with an increase in water depth (which increases prey dispersion). I tested this prediction through laboratory observations of Mexican Pacific lowlands garter snakes (T. validus) feeding on minnows in shallow (2 cm) and deep (3–7 cm) water. Members of this species are appropriate subjects because they are ecologically intermediate between the generalists and aquatic specialists studied by Drummond, and thus might be expected to show more variation in aquatic foraging behaviour than those species. T. validus showed significantly higher frequencies of crawling on the underwater substrate and of underwater strikes in the deep water than in the shallow water; i.e. increased water depth shifted the behaviour of these snakes toward that of aquatic specialists, thus supporting Drummond's hypothesis. Individuals of an aquatic specialist species, the narrow‐headed garter snake (T. rufipunctatus), showed less pronounced changes in behaviour with increased water depth. Western ribbon snakes (T. proximus), which feed primarily at the land–water interface (and are expected to act like terrestrial–aquatic generalists), typically refused to feed in deep water. Interspecific differences in underwater visual acuity may underly the behavioural differences among the three species by determining whether changes in foraging behaviour with water depth are advantageous. Information on phylogenetic relationships suggests that the facultative behaviour of T. validus may represent an intermediate stage in the evolution of aquatic specialization.
Male Competition over Access to Females in a Spider with Last‐Male Sperm Precedence
Authors: Schaefer Daniela , Uhl Gabriele 
Published: May 2003

AbstractAgonistic behaviour between male cellar spiders (Pholcus phalangioides) was investigated to test whether (1) size difference determines which male achieves access to the female, (2) males are able to monopolize access to the female until egg laying and whether (3) female resource value increases before egg laying because of last‐male sperm precedence. We further investigated whether (4) there is variation in time and energy spent on courtship and copulation depending on the degree of sperm competition, i.e. with or without rival present. In three experimental settings we introduced two males of either different or similar sizes, or a single male to a female. The mating units were constantly video‐observed until the females produced their first egg sac. Experience, ownership and female resource value in terms of body size was controlled. Our results show that larger males achieve almost exclusive access to females. Size symmetrical settings resulted in increased fighting activity and duration but dominance did not influence mating success. If copulations were disturbed by the rival male, copulations were terminated earlier in symmetrical settings compared with asymmetrical settings. In 94.8% of trials only one copulation took place, suggesting that the copulating male successfully monopolized access to the female. Males confronted with a rival copulated longer but courted significantly shorter than lone males. Although the last male to copulate sires 88% of the offspring in P. phalangioides, neither fighting nor courtship activity increased before the female laid a batch of eggs. This suggests that males have no indication of the timing of oviposition.
Bat Avoidance in Non‐Aerial Insects: The Silence Response of Signaling Males in an Acoustic Moth
Authors: Greenfield Michael D. , Baker Michelle 
Published: May 2003

AbstractWhile the evasive responses of many flying acoustic insects to aerial‐hawking bats are duly recognized and studied, the responses of non‐aerial insects to gleaning bats are generally overlooked. It has been assumed that acoustic insects are deaf to these predators because gleaning bat echolocation calls are typically low in amplitude, brief (1–3 ms) and very high in frequency (>60 kHz). We tested this assumption in a series of playback experiments with a moth (Achroia grisella) that uses hearing in both predator evasion and mating. We report that ultrasound pulses ≥78 dB peSPL (peak equivalent sound pressure level) and ≥1 ms in duration inhibit stationary males from broadcasting their own ultrasonic advertisement calls, provided that the pulsed stimuli are delivered at a repetition rate ≤30/s. Further analyses suggest that inhibition by pulsed ultrasound comprises two processes performed serially. First, a startle response with a latency <50 ms is elicited by a single pulse ≥1 ms duration. Here, a male misses broadcasting several calls over a 50–100 ms interval. Secondly, the startle may be extended as a silence response lasting several to many seconds if subsequent pulses occur at a rate ≤30/s. Call inhibition cannot represent a simple response to acoustic power because of the inverse interaction between pulse duration and rate. On the other hand, the temporal and energy characteristics of inhibitory stimuli match those of gleaning bat echolocation calls, and we infer that inhibition is a specialized defensive behavior by which calling males may avoid detection by eavesdropping bats.
Effect of Group Size on Individual and Collective Vigilance in Greater Rheas
Authors: Fernández Gustavo J. , Capurro Angel F. , Reboreda Juan C. 
Published: May 2003

AbstractWe studied the effect of group size on the proportion of time that greater rheas, Rhea americana, allocated to vigilance and feeding during the non‐breeding season. We tested whether: (1) the proportion of time that one bird allocates to vigilance (individual vigilance) decreases with group size, and (2) the proportion of time that at least one bird of the group is vigilant (collective vigilance) increases with group size. We analyzed video‐recordings of birds that were foraging alone or in groups from two to 12 birds. The proportion of time allocated to individual vigilance decreased and the proportion of time spent feeding increased with group size. In both cases the main significant difference was between birds foraging alone and in groups. Collective vigilance did not vary with group size and it was lower than expected if vigilance bouts were random or sequential. Our results indicate that rheas foraging in large groups would not receive the benefit of an increase in collective vigilance, although they could still benefit from a reduction of predation risk by the dilution effect.
Maternal Separation in Guinea‐Pigs: A Study in Behavioural Endocrinology
Authors: Wewers Dirk , Kaiser Sylvia , Sachser Norbert 
Published: May 2003

AbstractThe aim of this study was to elucidate the modulation of behaviour and endocrine stress responses of guinea‐pig pups by social and spatial factors in a maternal separation paradigm. The animals were kept in two colonies (each colony: nine males, 13 females and their offspring; enclosure size: 6 m2). Blood samples were taken from the ear vessels of eight male and eight female pups (aged 13–14 d) immediately before and 2 h after they were removed from their colony and were placed singly into a novel environment. Furthermore, eight male and eight female pups were tested in their home colony before and after 2 h of sepration from their mothers. Blood samples were taken from control animals (eight male and eight female pups) which remained in the home colonies together with their mothers. Additionally, the behaviour of 16 male and 16 female pups was recorded in their home colonies when their mothers were either present or absent. Male and female pups separated from their mothers showed a significantly higher locomotor activity, with females showing higher frequencies of distress calls, than pups whose mothers were present. The mother's absence did not cause a significant increase in serum cortisol concentrations in the male or the female offspring. This result is entirely different from the endocrine stress response of pups that were placed singly in an unknown environment. These animals showed a significant increase in their serum cortisol concentrations after 2 h of separation from their mothers. The absence of the mother led to distinct changes in the behaviour of the guinea‐pig pups. However, staying in the familiar social and spatial environment buffered the endocrine stress response that normally occurs because of maternal separation.
Safety from thromboembolism using intravenous immunoglobulin therapy in Kawasaki disease: Study of whole‐blood viscosity
Authors: Nishikawa Miki , Ichiyama Takashi , Hasegawa Masanari , Kawasaki Kozo , Matsubara Tomoyo , Furukawa Susumu 
Published: May 2003

Abstract
Background
: High‐dose intravenous infusions of immunoglobulin (IVIG) are well established as a standard therapy for Kawasaki disease (KD) for reducing the risk of coronary artery aneurysms. IVIG therapy might increase the blood viscosity both in vitro and in vivo, which has been reported as a risk factor for cardiovascular or cerebrovascular thromboembolism in adults.
Methods
: We measured the whole‐blood viscosity in vitro, serum IgG and albumin, and blood hematocrit in 10 patients with KD and 10 with non‐KD (five with acute encephalitis, one with sepsis, one with idiopathic thrombocytopenic purpura, one with Guillain−Barré syndrome, one with insulin‐dependent diabetes mellitus, and one with Evans syndrome) before and after IVIG therapy.
Results
: The blood viscosity increased significantly after IVIG therapy in the patients with non‐KD, but did not increase in those with KD.
Conclusion
: The results of the present study suggest that the use of IVIG therapy for KD might be relatively safe, with no risk of thromboembolism due to hyperviscosity.
Tension‐type headache in children: A clinical evaluation
Authors: Sarioglu Berrak , Erhan Elvan , Serdaroglu Gul , Doering Birgul Gokce , Erermis Serpil , Tutuncuoglu Sarenur 
Published: May 2003

Abstract
Background
: Anxiety and psychological stress are often pre‐existing factors which can trigger pediatric tension‐type headaches.
Methods
: Sixteen children (10 girls and six boys) aged between 7 and 18 years who fulfilled the International Headache Society (IHS) criteria for episodic tension‐type headache were included in the present study. Pain characteristics, associated symptoms, and stress‐triggering factors were evaluated. Psychiatric and psychosocial evaluations were performed according to DSM‐IV criteria.
Results
: Pain was bilateral in 93.7% of patients and bitemporal in 50% of children. The intensity of pain increased with motion and stress in more than half of the patients, while pain decreased with rest and massage in 43.7% of patients. Ten of the 16 (62.5%) patients were diagnosed as having a psychiatric disorder. The most common stress‐triggering factors were difficulty in adaptation at school and relationship problems with family members. All of the children reported 26 stress factors. Of these stress factors, 20 (76.9%) were reported by children diagnosed with psychiatric disorder.
Conclusion
: These results suggest that in children with tension‐type headache a thorough psychiatric evaluation should be performed to rule out underlying psychiatric disorders.
Pharmacokinetics and dosing of arbekacin in preterm and term newborn infants
Authors: Suzuki Keiji , Tanikawa Kouji , Matsuzaki Takashi 
Published: May 2003

Abstract
Background
: The objective of the present study was to determine pharmacokinetic variables and to characterize a new initial dosing regimen of arbekacin (ABK) for preterm and term newborn infants.
Patients and methods
: Subjects were 40 infants treated with ABK in a tertiary care neonatal unit over a period of 18 months. At birth, the infants were 23 5/7−40 0/7 weeks and weighed 530−3428 g. Serum ABK concentration was measured at two points in a course of treatment. Data were analyzed by a one‐compartment model to obtain volume of distribution (Vd) and clearance (CL) of ABK. These variables were correlated with the patients’ demographic and laboratory data. The new initial dosing regimen was determined based on these data.
Results
: Sixty pairs of blood samples were taken from the infants. They were divided into three groups: preterm early (PE), gestational age (GA) < 37 weeks and postnatal age (PNA) < 28 days; preterm late (PL), GA < 37 weeks and PNA ≥ 28 days; and term (T), GA ≥ 37 weeks and PNA < 28 days. The Vd was 0.50 ± 0.02, 0.48 ± 0.04, and 0.43 ± 0.03 L/kg, and CL was 0.59 ± 0.04, 1.12 ± 0.10, and 0.78 ± 0.09 mL/min per kg (mean ± SEM) in PE, PL, and T, respectively. The new dosing regimen is 5 mg/kg every 48 h, 5 mg/kg every 24 h, and 4 mg/kg every 24 h for PE, PL, and T, respectively.
Conclusions
: With the new dosing regimen, more infants achieved serum ABK levels within the optimal range than the conventional one.