bluuebunny/crossref_metadata_2025_split huggingface dataset:
A facilitative urea transporter is localized in the renal collecting tubule of the dogfishTriakis scyllia
Authors: Hyodo Susumu , Katoh Fumi , Kaneko Toyoji , Takei Yoshio 
Published: December 2003

SUMMARYReabsorption of filtered urea by the kidney tubule is essential for retaining high levels of urea in body fluids of marine elasmobranchs. To elucidate the mechanisms of urea reabsorption, we examined the distribution of a facilitative urea transporter (UT) in the kidney of the dogfish Triakis scyllia. We isolated a cDNA encoding a UT that is homologous to the facilitative UT cloned from another dogfish species, Squalus acanthias. The Triakis UT mRNA is abundantly expressed in the kidney, while low levels of expression were detected in the brain and liver. In the dogfish kidney, each nephron makes four turns and traverses repeatedly between bundle zone and sinus zone. In the bundle zone, the resulting five tubular segments are arranged in a countercurrent loop fashion. Immunohistochemistry using specific antibodies raised against the cloned UT revealed that, among the nephron segments, the UT is expressed exclusively in the final segment of the bundle zone, i.e. in the collecting tubule of the Triakis kidney. In contrast to the limited localization of UT, the transport enzyme Na+/K+-ATPase is distributed in the basolateral membrane of numerous tubular segments both in the sinus zone and the bundle zone. However, in the collecting tubule,Na+/K+-ATPase immunoreactivity was not detected. The present study suggests that the collecting tubule is responsible for the reabsorption of urea in the marine elasmobranch kidney. Other countercurrent segments may contribute to production of a driving force for facilitative diffusion of urea through the UT.
Cobalamin Status and Its Biochemical Markers Methylmalonic Acid and Homocysteine in Different Age Groups from 4 Days to 19 Years
Authors: Monsen Anne-Lise Bjørke , Refsum Helga , Markestad Trond , Ueland Per Magne 
Published: December 2003

AbstractBackground: Recent data indicate that cobalamin and folate status, including the metabolic markers methylmalonic acid (MMA) and total homocysteine (tHcy), undergo marked changes during childhood, particularly during the first year.Methods: Serum cobalamin, serum and whole-blood folate, and plasma MMA and tHcy were determined in a cross-sectional study of 700 children, ages 4 days to 19 years.Results: During the first 6 months, serum cobalamin was lower than and plasma MMA, tHcy, and serum folate were higher than the concentrations detected in the other age groups. In infants 6 weeks to 6 months of age, median MMA and tHcy concentrations were &gt;0.78 and &gt;75 μmol/L, respectively. In older children (&gt;6 months), serum cobalamin peaked at 3–7 years and then decreased, median plasma MMA remained low (&lt;0.26 μmol/L), median plasma tHcy was low (&lt;6 μmol/L) and increased from the age of 7 years on, and serum folate gradually decreased. Plasma MMA was inversely associated with cobalamin (r = −0.4) in both age groups, but across the whole range of cobalamin concentrations, MMA was markedly higher in infants (≤6 months) than in older children. Plasma tHcy showed a strong negative correlation to cobalamin (r = −0.52) but not to serum folate in infants ≤6 months. In older children, tHcy showed the expected association with both cobalamin (r = −0.48) and folate (r = −0.51).Conclusions: In infants 6 weeks to 6 months, concentrations of the metabolic markers MMA and tHcy were higher than in the other age groups and strongly correlated to cobalamin, whereas in older children, both makers showed correlations to cobalamin and folate concentrations documented in adults. Whether this metabolic profile in infants is explained by impaired cobalamin status, which in turn may have long-term effects on psychomotor development, remains to be addressed in intervention studies.
Physiologic Determinants of Endothelin Concentrations in Human Saliva
Authors: Xiang Sue , Denver Rachel , Bailey Michael , Krum Henry 
Published: December 2003

Abstract
Background: Salivary endothelin (ET) concentrations have been shown to correlate with disease severity in patients with chronic heart failure (CHF). We undertook the present study to evaluate the stability of salivary ET under different handling conditions to assess its suitability as a biochemical marker in screening, diagnosis, and management of CHF.
Methods: Saliva samples were collected from healthy individuals and/or CHF patients, subjected to different handling conditions, and then stored at −80 °C until assayed by an ELISA for ET.
Results: Salivary ET concentrations showed a time-dependent increase during storage at room temperature. After 72 h of incubation at room temperature, ET increased ∼2.8-fold (P = 0.03). Simultaneously, salivary big ET showed a time-dependent 11.2-fold decrease (P &lt;0.0001). This activity was blocked by an ET-converting enzyme (ECE) inhibitor, suggesting that these changes were attributable to ECE-dependent cleavage of endogenous big ET in saliva. Ex vivo conversion was also observed when samples were stored at 4 °C, but the magnitude of these changes was markedly smaller (P &lt;0.0001). Posture also affected salivary ET concentrations in CHF patients. With a change from supine to seated rest, salivary ET concentrations increased 1.5- and 1.8-fold after 20 and 40 min, respectively (P = 0.01). With a return to supine rest, salivary ET concentrations returned to baseline concentrations (P = 0.008).
Conclusions: These data suggest that saliva sampling and handling conditions could markedly affect measurement of salivary ET. In particular, care should be taken to minimize ECE-dependent enzymatic conversion of endogenous big ET in saliva.
Use of Lyophilized Calibrant Plasmas for Simplified International Normalized Ratio Determination with a Human Tissue Factor Thromboplastin Reagent Derived from Cultured Human Cells
Authors: van den Besselaar Anton M H P , Houdijk Wim P M 
Published: December 2003

Abstract
Background: For monitoring of treatment with oral anticoagulants, the clotting time obtained in the prothrombin time (PT) test is transformed to the International Normalized Ratio (INR) with use of a system-specific International Sensitivity Index (ISI). The calibrant plasma procedure (CPP) is an alternative approach to INR calculation based on the use of a set of lyophilized plasmas with assigned INRs.
Methods: With the CPP, a linear relationship is established between log(PT) and log(INR), using orthogonal regression. CPP was validated for Simplastin HTF, a new human tissue factor reagent derived from cultured human cells. CPP precision was assessed as the CV of the slope of the regression line. The accuracy of the CPP was determined by comparing the INR obtained with the CPP with that obtained with the established ISI-based reference method. INRs of the calibrants were assigned by different routes: by manufacturer (consensus labeling) or by use of Simplastin HTF or International Reference Preparations (IRPs; rTF/95 or RBT/90).
Results: The mean CV of the CPP regression slope ranged from 1.0% (Simplastin HTF reagent-specific INR) to 2.4% (INR assigned with rTF/95). INRs calculated with the CPP were similar to those obtained with the reference method, but when the routes for assigning INRs to the calibrant plasmas were compared, the mean difference in INR between CPP and the reference method was smaller with Simplastin HTF reagent-specific values. In several (but not all) cases, this difference was significant (P &lt;0.05, t-test).
Conclusion: CPP can be used for local INR determination, but better precision and accuracy are obtained with reagent-specific INRs compared with INR assignment by consensus labeling or IRP.
Quantitative Analysis and Prognostic Implication of SARS Coronavirus RNA in the Plasma and Serum of Patients with Severe Acute Respiratory Syndrome
Authors: Ng Enders K O , Hui David S , Chan K C Allen , Hung Emily C W , Chiu Rossa W K , Lee Nelson , Wu Alan , Chim Stephen S C , Tong Yu K , Sung Joseph J Y , Tam John S , Lo Y M Dennis 
Published: December 2003

Abstract
Background: The availability of an early diagnostic tool for severe acute respiratory syndrome (SARS) would have major public health implications. We investigated whether the SARS coronavirus (SARS-CoV) can be detected in serum and plasma samples during the early stages of SARS and studied the potential prognostic implications of such an approach.
Methods: We developed two real-time quantitative reverse transcription-PCR (RT-PCR) assays, one for the polymerase and the other for the nucleocapsid region of the virus genome, for measuring the concentration of SARS-CoV RNA in serum/plasma samples from SARS patients. Plasma samples were obtained from 12 confirmed SARS patients on the day of hospital admission, as well as on days 7 and 14 after fever onset. Serum samples were also obtained from 23 confirmed SARS patients on the day of hospital admission, 11 of whom subsequently required intensive care. Viral RNA was extracted from the plasma/serum samples. The extracted RNA was subjected to analysis by the RT-PCR assays.
Results: The RT-PCR system for the polymerase region detected SARS-CoV RNA in 50% of plasma and 78% of serum samples from SARS patients during the first week of illness. The detection rates for plasma dropped to 25% at day 14 after fever onset. The median serum SARS-CoV concentrations in patients who required and did not require intensive care unit admission during the course of hospitalization were 5800 and 140 copies/mL, respectively (Mann–Whitney test, P &lt;0.005). These data were confirmed by the RT-PCR system for the nucleocapsid region, which showed an even higher detection rate of 87%. The correlation between the results obtained by the two RT-PCR systems was high (Pearson correlation analysis, r = 0.998; P &lt;0.001).
Conclusion: Plasma/serum SARS-CoV quantification represents a potentially useful early diagnostic and prognostic tool for SARS.
Inductively Coupled Plasma Mass Spectrometric Analysis of Calcium Isotopes in Human Serum: A Low-Sample-Volume Acid-Equilibration Method
Authors: Chen Zhensheng , Griffin Ian J , Kriseman Yana L , Liang Lily K , Abrams Steven A 
Published: December 2003

Abstract
Background: Analytical methods for measuring the calcium isotope distribution in enriched human serum samples that use low blood volumes, simple preparation methods, and rapid analysis are important in clinical studies of calcium kinetics. Previously, sample preparation by oxalate precipitation typically required 500 μL of serum. This method was time-consuming, and the blood volume required was limiting in circumstances when only a small amount of serum could be obtained.
Methods: Serum was collected from humans who were administered 42Ca, and 20 μL of serum was mixed with 2 mL of 0.22–0.67 mol/L HNO3 at room temperature for between 1 min and 16 h. The 42Ca/43Ca ratio in the supernatant was measured by a magnetic sector inductively coupled plasma mass spectrometer (ICP-MS). Calcium isotope ratios from these equilibration solutions were compared with data from oxalate-precipitated serum samples to determine the optimum equilibrium time and the effect of acid concentration on equilibrium.
Results: Various amounts of aggregated particles developed in different acid-serum mixtures. These affected the time required for isotope equilibration in the mixture. The shortest equilibrium time needed for the calcium isotopes varied from 1 to 6 h for samples acidified with 0.22–0.45 mol/L HNO3. Data obtained from these solutions were consistent with data from oxalate-precipitated calcium. The precision of 42Ca/43Ca ratio measurements was better than 0.5%.
Conclusions: We have developed a simple, rapid sample preparation technique for ICP-MS analysis in which 20 μL of serum can be used for accurate measurement of the calcium isotope distribution in a sample with good precision and a rapid analysis time.
Leaders of progressions in wild mixed‐species troops of saddleback (Saguinus fuscicollis) and mustached tamarins (S. mystax), with emphasis on color vision and sex
Authors: Smith Andrew C. , Buchanan‐Smith Hannah M. , Surridge Alison K. , Mundy Nicholas I. 
Published: December 2003

AbstractLeadership of travel progression is an important aspect of group living. It is widely believed that trichromacy evolved to facilitate the detection and selection of fruit in the dappled light of a forest. Further, it has been proposed that in New World primate species, which typically contain a range of color vision phenotypes, at least one female in a group will be trichromatic (i.e., having three types of visual pigment, in contrast to the two types of pigment found in dichromatic individuals) and will lead the group to fruiting trees. We examine progression leadership within two wild mixed‐species troops of saddleback (Saguinus fuscicollis) and mustached (Saguinus mystax) tamarins over a complete year. As whole units, the mixed‐species troops were most frequently led by a mustached tamarin. This is the first time that mixed‐species group leadership and individual leadership have been quantified in these tamarin species. In terms of single‐species intragroup leadership, neither the visual status (dichromatic or trichromatic) nor the sex of individuals had a consistent effect across species. Saddleback tamarin groups were led by males more frequently than females, while evidence suggests that mustached tamarins may be female‐led. The notion that all groups contain at least one trichromatic female that leads the troop to feeding trees was not supported. Am. J. Primatol. 61:145–157, 2003. © 2003 Wiley‐Liss, Inc.
Patterns of female dominance in Propithecus diadema edwardsi of Ranomafana national park, Madagascar
Authors: Pochron Sharon T. , Fitzgerald John , Gilbert Christopher C. , Lawrence Diana , Grgas Marie , Rakotonirina Georges , Ratsimbazafy Raymond , Rakotosoa Rémi , Wright Patricia C. 
Published: December 2003

AbstractMany lemur species are characterized by some form of female dominance, ranging from female feeding priority to complete female dominance, although this is a rare trait in primates and other mammals. The status of the Milne‐Edwards' sifaka (Propithecus diadema edwardsi), a diurnal lemur, is ambiguous. Some short‐term studies have found little or no aggression. The aim of the current, long‐term study was to quantify the intersexual‐dominance patterns of this sifaka. The distribution, outcome, and context of aggressive interactions were studied in four groups of wild sifakas. The majority of intersexual aggressive interactions were decided, with the loser expressing submissive behavior. Intersexual aggressive interactions occurred in all social contexts, and within all social contexts the females won the vast majority (92.7–96.0%) of aggressive interactions. While aggression rates were low (0.22/hr), this evidence suggests female dominance. We propose that female dominance exists because it provides a fitness advantage to both males and females. Am. J. Primatol. 61:173–185, 2003. © 2003 Wiley‐Liss, Inc.
Throwing behavior and mass distribution of stone selection in tufted capuchin monkeys (Cebus apella)
Authors: Cleveland A. , Rocca A.R. , Wendt E.L. , Westergaard G.C. 
Published: December 2003

AbstractCannell [Journal of Archaeological Science 29:335–339, 2002] argued that sex‐based differences among humans in terms of the mass of chosen throwing stones could be used to infer body mass and patterns of sexual dimorphism in early hominids from Olduvai and Koobi Fora by examining the mass distributions of unaltered stone tools at those sites. We examined this hypothesis in tufted capuchin monkeys using a comparative approach, by investigating the relationships among body mass, sex, stone weight preference, and accuracy in a throwing task. The subject sample consisted of nine monkeys trained to perform an aimed‐throwing task in which a food reward could be obtained by throwing a stone into a bucket. We found that 1) the subjects showed a strong mean stone mass preference; 2) the females chose heavier stones than the males, in terms of absolute mean selected stone mass and selected stone mass relative to body mass; 3) subjects threw more accurately when they used stones of preferred mass vs. stones of nonpreferred mass; and 4) overall, the males were more accurate in the throwing task than the females. We conclude that capuchins are highly selective when choosing throwing stones, and that this confers an advantage for throwing accuracy. Our results indicate that the sexually dimorphic pattern in stone mass preference observed among humans does not generalize to Cebus apella. We suggest that researchers examining this pattern in humans in an attempt to explain early hominid patterns of dimorphism and behavior should take into account not only stone weight preference, but also its adaptive advantage. Am. J. Primatol. 61:159–172, 2003. © 2003 Wiley‐Liss, Inc.
Sex difference in chimpanzee handedness
Authors: Corp Nadia , Byrne Richard W. 
Published: December 2003

AbstractChimpanzees at Mahale, Tanzania, show strong individual hand preferences when they use bimanual actions in processing the fruit of Saba florida and Citrus lemon. The direction of hand preference differs between the sexes: most males are left‐handed, whereas most females are right‐handed. Monkeys and apes are considered to lack “handedness,” in the sense of a population mode of left‐ or right‐hand preference; they are normally ambidextrous. Indeed, strong individual preferences were previously seldom found in natural tasks. We propose that lateralization of manual actions becomes advantageous in bimanual tasks, which involve role differentiation between the hands and a need to combine power and precision. If the pattern of lateralization found here reflects the ancestral state, common to chimpanzees and humans, this may explain why, in modern humans, women tend more strongly to be right‐handed than men, who include a larger minority of left‐handers. Am J Phys Anthropol, 2003. © 2003 Wiley‐Liss, Inc.
Ossification and midline shape changes of the human fetal cranial base
Authors: Jeffery Nathan , Spoor Fred 
Published: December 2003

AbstractAn appreciation of ontogenetic changes to the cranial base is important for understanding the evolution of modern human skull form. Using geometric morphometric techniques, this study explores midline shape variations of the basicranium and midface during human prenatal ontogeny. In particular, the analysis sets out to explore shape variations associated with endochondral ossification and to reassess shape variations previously observed on the basis of angular measures.Fifty‐four formalin‐preserved human fetuses were imaged using high‐resolution MRI. Coordinates for 10 landmarks defining the midline basicranium and midface were acquired and areas of ossification in the midline basioccipital, basisphenoid, and presphenoid cartilages were measured as percentages of overall cranial base area. The results show shape variations with increasing fetal size that are consistent with cranial base retroflexion, anterior facial projection and dorsal facial rotation. These growth variations are centered on the midsphenoid area and are associated with disproportionate variations of sphenoid height and length. Small but significant correlations were observed between ossification of the presphenoid cartilage and components of shape that described, among other variations, sphenoid shortening. While ossification cannot be directly linked with the shape variations observed, it seems likely that bone formation plays a role in modulating the influence of other factors on the fetal cranial base. Am J Phys Anthropol 2003. © 2003 Wiley‐Liss, Inc.
Sex differences in play among western lowland gorilla (Gorilla gorilla gorilla) infants: Implications for adult behavior and social structure
Authors: Maestripieri Dario , Ross Stephen R. 
Published: December 2003

AbstractMammalian play is believed to improve motor skills as well as facilitate the development of social relationships. Given the marked sexual dimorphism in gorilla body size and the role assumed by the male in protecting the group from conspecifics and predators, the motor‐training hypothesis of play predicts that male infants should exhibit higher frequencies of social play than female infants, and that males should prefer to play with other males. Given that adult female gorillas are strongly attracted to adult breeding males and form only weak social bonds with unrelated adult females, the social‐relationship hypothesis of play predicts that female infants should prefer to play with males. These hypotheses were tested in a 22‐month study of 12 gorilla infants, aged between 0–5 years, living in three zoological parks in Chicago and Atlanta. Consistent with the hypotheses, male infants played more than female infants did, and both male and female infants preferred to play with males rather than with females. These findings suggest that sex differences in play in the great apes and other primates can be predicted by the characteristics of adult behavior and social structure above and beyond the patterns of sex‐biased dispersal or coalition formation with same‐sex kin. Am J Phys Anthropol, 2003. © 2003 Wiley‐Liss, Inc.
Social organization of the golden brown mouse lemur (Microcebus ravelobensis)
Authors: Weidt Andrea , Hagenah Nicole , Randrianambinina Blanchard , Radespiel Ute , Zimmermann Elke 
Published: December 2003

AbstractOur study provides the first data on the social organization of the golden brown mouse lemur, a nocturnal primate discovered in northwestern Madagascar in 1994. The study was carried out in two 6‐month field periods during the dry season, covering time before and during the mating season. The spatial and temporal distributions of the sexes in the population were investigated by mark/recapture and radiotelemetry. Focal observations and the determination of sleeping associations provided further insights into the sociality of this solitary forager. High intra‐ and intersexual home‐range overlaps occurred throughout the study. In general, individuals of both sexes had spatial access to more than one conspecific of the same and the opposite sex. We found no indication for spatial monopolization of females by certain males. These results suggest a dispersed multimale/multifemale system with a promiscuous mating pattern. Individuals showed temporal stability in their home range locations and interacted regularly with conspecifics. Five sleeping groups were identified during the study period: one female group and four mixed‐sex groups. Even though sleeping sites were changed frequently, sleeping‐group compositions remained stable over time. Thermoregulatory constraints are the most likely explanation for sleeping‐group composition with members of both sexes in this species. Mixed‐sex sleeping groups can be described as the basic social unit within this dispersed multimale/multifemale society. Am J Phys Anthropol, 2003. © 2003 Wiley‐Liss, Inc.