bluuebunny/crossref_metadata_2025_split huggingface dataset:
Which young physicians are satisfied with their work? A prospective nationwide study in Norway
Authors: Finset Kristine Benedictow , Gude Tore , Hem Erlend , Tyssen Reidar , Ekeberg Oivind , Vaglum Per 
Published: June 2005

Abstract

Background
Few studies have investigated personality and medical school variables in regard to job satisfaction after graduation. It is of great importance to investigate these factors because this information may be used in the recruitment/admittance process to medical schools, and possibly to improve medical education.

Methods
We conducted a nationwide prospective 10-year follow-up study of medical students at all medical schools in Norway. They were approached three times during their medical training: at very beginning (T1), in the middle (T2), in the last year of medical school (T3), and then four years after graduation (T4). There were 210 participants who responded on all four occasions. Job satisfaction was measured with the Job Satisfaction Scale, which was used as the outcome variable. In addition to conducting multiple regression analysis for the total sample, we also conducted similar analyses separately for men and women.

Results
Among the demographic and personality variables, 'having a father who is a physician' and 'interpersonal functioning (being withdrawn)' were significantly associated with job satisfaction at T4. Among the medical school variables, 'well-being with peers', 'identification with the doctor's role at the end of curriculum', 'perceived medical school stress', and 'perceived clinical skills' were significantly associated with job satisfaction. In the multiple regression analysis only 'father as a physician' and 'perceived clinical skills' yielded an independent influence on the outcome variable in separate analyses within sub-groups of male and female students, 'perceived clinical skills' differentiated among woman only, while 'well-being with peers' differentiated only among men.

Conclusion
The main finding of this study is that the young physicians who are the most satisfied in their work are those whose fathers are physicians and those who have a high level of perceived clinical skills at the end of medical school. There are also differences in regard to predictors of job satisfaction among men and women. These findings indicate that medical schools should invest substantial effort in clinical skills training, and this seems to be especially important among female students.
Mouse intraflagellar transport proteins regulate both the activator and repressor functions of Gli transcription factors
Authors: Liu Aimin , Wang Baolin , Niswander Lee A. 
Published: June 2005

Intraflagellar transport (IFT) is an active event in which cargo is transported along microtubules by motor proteins such as kinesin and dynein. IFT proteins are required for the formation and maintenance of flagella and cilia. We have previously shown that mouse mutants for two IFT proteins, IFT88 and IFT172, as well as Kif3a, a subunit of mouse kinesin 2, exhibit ventral spinal cord patterning defects that appear to result from reduced hedgehog(Hh) signaling. Although genetic epistasis experiments place IFT proteins downstream of the Hh receptor and upstream of the Gli transcription factors,the mechanism by which IFT regulates Gli function is unknown.The developing limb provides an excellent system to study Hh signaling, in particular as it allows a biological and molecular readout of both Gli activator and repressor function. Here we report that homozygous mutants for flexo (Fxo), a hypomorphic allele of mouse IFT88 generated in our ENU mutagenesis screen, exhibit polydactyly in all four limbs. Molecular analysis indicates that expression domains of multiple posteriorly restricted genes are expanded anteriorly in the mutant limbs, similar to loss of Gli3 transcriptional repressor function. Sonic hedgehog (Shh) expression is normal, yet Ptch1 and Gli1, two known targets of Hh signaling, are greatly reduced, consistent with loss of Shh signaling. Expression of Gli3 and Hand2 in the mutant limb indicates that the limb prepattern is abnormal. In addition, we show that partial loss-of-function mutations in another mouse IFT gene, Ift52(Ngd5), result in similar phenotypes and abnormal Hh signaling as Fxo, indicating a general requirement for IFT proteins in Hh signaling and patterning of multiple organs. Analysis of Ift88 and Shh double mutants indicates that, in mouse, IFT proteins are required for both Gli activator and repressor functions, and Gli proteins are insensitive to Hh ligand in the absence of IFT proteins. Finally, our biochemical studies demonstrate that IFT proteins are required for proteolytic processing of Gli3 in mouse embryos. In summary, our results indicate that IFT function is crucial in the control of both the positive and negative transcriptional activities of Gli proteins, and essential for Hh ligand-induced signaling cascade.
Do monarch butterflies use polarized skylight for migratory orientation?
Authors: Stalleicken Julia , Mukhida Maya , Labhart Thomas , Wehner Rüdiger , Frost Barrie , Mouritsen Henrik 
Published: June 2005

SUMMARY
To test if migratory monarch butterflies use polarized light patterns as part of their time-compensated sun compass, we recorded their virtual flight paths in a flight simulator while the butterflies were exposed to patches of naturally polarized blue sky, artificial polarizers or a sunny sky. In addition, we tested butterflies with and without the polarized light detectors of their compound eye being occluded. The monarchs' orientation responses suggested that the butterflies did not use the polarized light patterns as a compass cue, nor did they exhibit a specific alignment response towards the axis of polarized light. When given direct view of the sun, migratory monarchs with their polarized light detectors painted out were still able to use their time-compensated compass: non-clockshifted butterflies, with their dorsal rim area occluded, oriented in their typical south–southwesterly migratory direction. Furthermore, they shifted their flight course clockwise by the predicted ∼90° after being advance clockshifted 6 h. We conclude that in migratory monarch butterflies, polarized light cues are not necessary for a time-compensated celestial compass to work and that the azimuthal position of the sun disc and/or the associated light-intensity and spectral gradients seem to be the migrants' major compass cue.
Specificity of the fluorescein transport process in Malpighian tubules of the cricketAcheta domesticus
Authors: Neufeld Douglas S. G. , Kauffman Ross , Kurtz Zachary 
Published: June 2005

SUMMARYWe demonstrate the presence of an efficient, multispecific transport system for excretion of organic anions in the Malpighian tubules of the cricket Acheta domesticus using fluorescein (FL) as a model substrate. Malpighian tubules rapidly accumulated FL via a high affinity process(Km=7.75 μmol l–1); uptake was completely eliminated by the prototypical organic anion transport inhibitor probenecid (1 mmol l–1), but not by p-aminohippuric acid (3 mmol l–1). FL uptake was inhibited by monocarboxylic acids at a high concentration (3 mmol l–1), and inhibition was more effective with an increase in the carbon chain of the monocarboxylic acid (37% inhibition by 5-carbon valeric acid, and 89% inhibition by 7-carbon caprylic acid). Likewise, tests using a series of aliphatic glutathione conjugates indicated that only the compound with the longest side-chain(decyl-glutathione) significantly inhibited FL uptake (81% inhibition). FL uptake was inhibited by a number of xenobiotics, including a plant alkaloid(quinine), herbicides (2,4-dichlorophenoxyacetic acid and 4-(2,4-dichlorophenoxy)-butyric acid), and the insecticide metabolites malathion monocarboxylic acid (MMA) and 3-phenoxybenzoic acid (PBA),suggesting that this transport system plays an active role in excretion of xenobiotics from Acheta by Malpighian tubules. HPLC quantification of MMA and PBA accumulation into Malpighian tubules verified that MMA accumulation was via a mediated transport process, but suggested that PBA accumulation was by nonspecific binding. The presence of a transport system in Malpighian tubules that handles at least one pesticide metabolite(MMA) suggests that transport processes could be a mechanism conferring resistance to xenobiotic exposure in insects.
Patterns of red muscle strain/activation and body kinematics during steady swimming in a lamnid shark, the shortfin mako (Isurus oxyrinchus)
Authors: Donley Jeanine M. , Shadwick Robert E. , Sepulveda Chugey A. , Konstantinidis Peter , Gemballa Sven 
Published: June 2005

SUMMARYThe dynamics of steady swimming were examined in the shortfin mako(Isurus oxyrinchus), a member of the cartilaginous fish family Lamnidae, a family known for their morphological adaptations for high-performance locomotion and their similarity in hydromechanical design to tunas. Patterns of red muscle (RM) strain (i.e. relative length change) and activation were quantified at two axial positions (∼0.4 and 0.6L,where L is total body length), using sonomicrometry and electromyography (EMG), and correlated with simultaneous measurements of dorsal midline kinematics during steady swimming (∼0.5–1 Ls–1). RM strain varied longitudinally with strain amplitudes ranging from 5.5±1.1% (s.e.m.) in the anterior to 8.7±0.9% in the posterior. We found no significant longitudinal variation in patterns of RM activation, with mean onset of activation occurring at 83–84° (90° is peak length) and offset at 200–210° at both body positions. Likewise, duty cycles were similar:35.5±1.0% in the anterior and 32.2±1.6% in the posterior. Comparison of the timing of waves of dorsal midline curvature and predicted strain relative to measured RM strain revealed a phase shift between RM shortening and local body bending. Furthermore, when the body is bent passively, RM shortens synchronously with the surrounding white muscle (WM)and skin, as expected. During active swimming, peaks in RM strain were delayed relative to peaks in WM strain by a mean of ∼10% of the tailbeat cycle,with one individual as high as ∼17% in the anterior and nearly 50% in the posterior. The longitudinal consistency in the EMG/strain phase relationship in the mako is similar to that in the leopard shark, suggesting a consistent trend among sharks using different locomotor modes. However, unlike in the leopard shark, RM shortening in the mako is physically uncoupled from deformation of the surrounding body during steady swimming, a characteristic shared between the mako and tunas.
Beta-adrenergic control of plasma glucose and free fatty acid levels in the air-breathing African catfishClarias gariepinusBurchell 1822
Authors: van Heeswijk Johannes C. F. , Vianen Gerjanne J. , van den Thillart Guido E. E. J. M. , Zaagsma Johan 
Published: June 2005

SUMMARYIn several water-breathing fish species, β-adrenergic receptor stimulation by noradrenaline leads to a decrease in plasma free fatty acid(FFA) levels, as opposed to an increase in air-breathing mammals. We hypothesised that this change in adrenergic control is related to the mode of breathing. Therefore, cannulated air-breathing African catfish were infused for 90 min with noradrenaline or with the nonselective β-agonist,isoprenaline. To identify the receptor type involved, a bolus of either a selective β1-antagonist (atenolol) or a selectiveβ 2-antagonist (ICI 118,551) was injected 15 min prior to the isoprenaline infusion. Both noradrenaline and isoprenaline led to an expected rise in glucose concentration. Isoprenaline combined with both theβ 1- and β2-antagonist led to higher glucose concentrations than isoprenaline alone. This could indicate the presence of a stimulatory β-adrenoceptor different from β1 andβ 2-adrenoceptors; these two receptors thus seemed to mediate a reduction in plasma glucose concentration. Both noradrenaline and isoprenaline led to a significant decrease in FFA concentration. Whereas theβ 1-antagonist had no effect, the β2-antagonist reduced the decrease in FFA concentration, indicating the involvement ofβ 2-adrenoceptors. It is concluded that the air-breathing African catfish reflects water-breathing fish in the adrenergic control of plasma FFA and glucose levels.
Determination of the exact copy numbers of particular mRNAs in a single cell by quantitative real-time RT-PCR
Authors: Wagatsuma Akiko , Sadamoto Hisayo , Kitahashi Takashi , Lukowiak Ken , Urano Akihisa , Ito Etsuro 
Published: June 2005

SUMMARY
Gene expression is differently regulated in every cell even though the cells are included in the same tissue. For this reason, we need to measure the amount of mRNAs in a single cell to understand transcription mechanism better. However, there are no accurate, rapid and appropriate methods to determine the exact copy numbers of particular mRNAs in a single cell. We therefore developed a procedure for isolating a single, identifiable cell and determining the exact copy numbers of mRNAs within it. We first isolated the cerebral giant cell of the pond snail Lymnaea stagnalis as this neuron plays a key role in the process of memory consolidation of a learned behavior brought about by associative learning of feeding behavior. We then determined the copy numbers of mRNAs for the cyclic AMP-responsive element binding proteins (CREBs). These transcription factors play an important role in memory formation across animal species. The protocol uses two techniques in concert with each other: a technique for isolating a single neuron with newly developed micromanipulators coupled to an assay of mRNAs by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR). The molecular assay determined the mRNA copy numbers, each of which was compared with a standard curve prepared from cDNA solutions corresponding to the serially diluted solutions of Lymnaea CREB mRNA. The standard curves were linear within a range of 10 to 105 copies, and the intra-assay variation was within 15%. Each neuron removed from the ganglia was punctured to extract the total RNA directly and was used for the assay without further purification. Using this two-step procedure, we found that the mRNA copy number of CREB repressor (CREB2) was 30–240 in a single cerebral giant cell, whereas that of CREB activator (CREB1) was below the detection limits of the assay (&lt;25). These results suggest that the CREB cascade is regulated by an excess amount of CREB2 in the cerebral giant cells. Our procedure is the only quantitative analysis for elucidation of the dynamics of gene transcription in a single cell.
Maximal metabolic rates during voluntary exercise, forced exercise, and cold exposure in house mice selectively bred for high wheel-running
Authors: Rezende Enrico L. , Chappell Mark A. , Gomes Fernando R. , Malisch Jessica L. , Garland Theodore 
Published: June 2005

SUMMARYSelective breeding for high wheel-running activity has generated four lines of laboratory house mice (S lines) that run about 170% more than their control counterparts (C lines) on a daily basis, mostly because they run faster. We tested whether maximum aerobic metabolic rates(V̇O2max) have evolved in concert with wheel-running, using 48 females from generation 35. Voluntary activity and metabolic rates were measured on days 5+6 of wheel access (mimicking conditions during selection), using wheels enclosed in metabolic chambers. Following this, V̇O2max was measured twice on a motorized treadmill and twice during cold-exposure in a heliox atmosphere (HeO2). Almost all measurements, except heliox V̇O2max, were significantly repeatable. After accounting for differences in body mass(S&lt;C) and variation in age at testing, S and C did not differ in V̇O2max during forced exercise or in heliox, nor in maximal running speeds on the treadmill. However, running speeds and V̇O2max during voluntary exercise were significantly higher in S lines. Nevertheless, S mice never voluntarily achieved the V̇O2max elicited during their forced treadmill trials, suggesting that aerobic capacity per se is not limiting the evolution of even higher wheel-running speeds in these lines. Our results support the hypothesis that S mice have genetically higher motivation for wheel-running and they demonstrate that behavior can sometimes evolve independently of performance capacities. We also discuss the possible importance of domestication as a confounding factor to extrapolate results from this animal model to natural populations.
Molecular characterization and expression of the UV opsin in bumblebees:three ommatidial subtypes in the retina and a new photoreceptor organ in the lamina
Authors: Spaethe Johannes , Briscoe Adriana D. 
Published: June 2005

SUMMARYUltraviolet-sensitive photoreceptors have been shown to be important for a variety of visual tasks performed by bees, such as orientation, color and polarization vision, yet little is known about their spatial distribution in the compound eye or optic lobe. We cloned and sequenced a UV opsin mRNA transcript from Bombus impatiens head-specific cDNA and, using western blot analysis, detected an eye protein band of ∼41 kDa,corresponding to the predicted molecular mass of the encoded opsin. We then characterized UV opsin expression in the retina, ocelli and brain using immunocytochemistry. In the main retina, we found three different ommatidial types with respect to the number of UV opsin-expressing photoreceptor cells,namely ommatidia containing two, one or no UV opsin-immunoreactive cells. We also observed UV opsin expression in the ocelli. These results indicate that the cloned opsin probably encodes the P350 nm pigment, which was previously characterized by physiological recordings. Surprisingly, in addition to expression in the retina and ocelli, we found opsin expression in different parts of the brain. UV opsin immunoreactivity was detected in the proximal rim of the lamina adjacent to the first optic chiasm, which is where studies in other insects have found expression of proteins involved in the circadian clock, period and cryptochrome. We also found UV opsin immunoreactivity in the core region of the antennal lobe glomeruli and different clusters of perikarya within the protocerebrum, indicating a putative function of these brain regions, together with the lamina organ, in the entrainment of circadian rhythms. In order to test for a possible overlap of clock protein and UV opsin spatial expression, we also examined the expression of the period protein in these regions.
Nitric oxide and the control of catecholamine secretion in rainbow trout Oncorhynchus mykiss
Authors: McNeill B. , Perry S. F. 
Published: June 2005

SUMMARY
An in situ saline-perfused posterior cardinal vein preparation was used to assess the role of nitric oxide (NO) in the regulation of basal and stimulus-evoked catecholamine secretion from rainbow trout Oncorhynchus mykiss chromaffin cells. Addition of the NO donor, sodium nitroprusside(SNP) to the inflowing perfusate abolished catecholamine secretion during electrical field stimulation, thereby establishing the potential for NO to act as a potent inhibitor of catecholamine release. A possible role for endogenously produced NO was established by demonstrating that stimulus-evoked(depolarizing levels of KCl or electrical field stimulation) catecholamine secretion was markedly stimulated in the presence of the nitric oxide synthase(NOS) inhibitors l-NAME and 7-NI. Although in vitroexperiments demonstrated that catecholamine degradation was enhanced by NO in a dose-dependent manner, the dominant factor contributing to the reduction in catecholamine appearance in the perfusate was specific inhibition of catecholamine secretion. Subsequent experiments were performed to identify the NOS isoform(s) contributing to the inhibition of stimulus-evoked catecholamine secretion. Inducible NOS (iNOS; an enzyme that can be activated in the absence of Ca2+), although present in the vicinity of the chromaffin cells(based on mRNA measurements), does not appear to play a role because stimulus-evoked NO production was eliminated during perfusion with Ca2+-free saline. The potential involvement of endothelial NOS(eNOS) was revealed by showing that hypoxic perfusate evoked NO production and corresponded with an inhibition of stimulus-evoked catecholamine secretion;chemical removal of the endothelium (using saponin) prevented the production of NO during hypoxia. However, because removal of the endothelium did not affect NO production during electrical field stimulation, it would appear that the neuronal form of NOS (nNOS) is the key isoform modulating catecholamine secretion from trout chromaffin cells.
The behavioural transition from straight to curve walking: kinetics of leg movement parameters and the initiation of turning
Authors: Dürr Volker , Ebeling Wiebke 
Published: June 2005

SUMMARYThe control of locomotion requires the ability to adapt movement sequences to the behavioural context of the animal. In hexapod walking, adaptive behavioural transitions require orchestration of at least 18 leg joints and twice as many muscle groups. Although kinematics of locomotion has been studied in several arthropod species and in a range of different behaviours,almost nothing is known about the transition from one behavioural state to another. Implicitly, most studies on context-dependency assume that all parameters that undergo a change during a behavioural transition do so at the same rate. The present study tests this assumption by analysing the sequence of kinematic events during turning of the stick insect Carausius morosus, and by measuring how the time courses of the changing parameters differ between legs. Turning was triggered reliably at a known instant in time by means of the optomotor response to large-field visual motion. Thus, knowing the start point of the transition, the kinematic parameters that initiate turning could be ranked according to their time constants.Kinematics of stick insect walking vary considerably among trials and within trials. As a consequence, the behavioural states of straight walking and curve walking are described by the distributions of 13 kinematic parameters per leg and of orientation angles of head and antennae. The transitions between the behavioural states are then characterised by the fraction of the variance within states by which these distributions differ,and by the rate of change of the corresponding time courses. The antennal optomotor response leads that of the locomotor system. Visually elicited turning is shown to be initiated by stance direction changes of both front legs. The transition from straight to curve walking in stick insects follows different time courses for different legs, with time constants of kinematic parameters ranging from 1.7 s to more than 3 s. Therefore, turning is a behavioural transition that involves a characteristic orchestration of events rather than synchronous parallel actions with a single time constant.