bluuebunny/crossref_metadata_2025_split huggingface dataset:
Predicting daytime carbon isotope ratios of atmospheric CO2 within forest canopies
Authors: Buchmann N. , Brooks J. R. , Ehleringer J. R. 
Published: March 2003

Summary

While measurements of leaf carbon isotope ratios (13C/12C) in terrestrial ecosystems have become more frequent, interpreting these data can remain a challenge in well developed canopies: the variation in leaf δ13C (δ13Cp) values is influenced by both the variation in δ13C of source air (δ13Ca) and by photosynthetic carbon isotope discrimination (Δ). However, source air information is often unavailable, limiting the interpretation of δ13Cp, particularly in dense stands.
In this synthesis we found that about 70% of the observed variation in δ13Cp values within the canopy was influenced by changes in Δ, and that about 30% was determined by source air effects. Significant shifts in δ13Ca occur in canopies with high leaf area, predominantly within 1 m above the forest floor. In complex canopies, particularly in the understorey, source air effects cannot be neglected if δ13Cp measurements are used to calculate Δ and ci/ca ratios [ratio of internal CO2 concentration in the mesophyll airspaces (ci) to the ambient atmospheric concentration of CO2 (ca)].
We modelled δ13Ca of daytime source air for deciduous and coniferous forests in boreal, temperate and tropical biomes. An inverse regression model with easily available input variables accounted for about 90% of the variation in daytime δ13Ca values throughout the canopy.
In open canopies with leaf area index (L) of <2·5 or at canopy heights ≥1 m, the within‐canopy daytime δ13Ca differences are negligible, and variations in δ13Cp are associated primarily with changes in Δ. Then, one can use the easily available carbon isotope ratio of the troposphere (δ13Ctrop) as a substitute for δ13Ca to calculate Δ to within ±0·4‰.
In canopies with L values >2·5, and at canopy heights <1 m, our model is recommended for calculating canopy δ13Ca values when direct measurements are not feasible. Although δ13Ca is highly variable near the forest floor in those dense forests, our model is more accurate and precise for estimating δ13Ca within 1 m above the forest floor than using δ13Ctrop throughout the canopy (−0·2‰ ± 1·5 versus −1·4‰ ± 1·1).
Metabolic recovery in the Desert Iguana (Dipsosaurus dorsalis) following activities of varied intensity and duration
Authors: Hancock T. V. , Gleeson T. T. 
Published: March 2003

Summary

Elevated oxygen consumption during recovery is the majority of total metabolic costs associated with short vigorous activity, thus any assessment of total costs associated with such activity should also examine the excess postexercise oxygen consumption (EPOC). This study examined EPOC and total metabolic costs in Dipsosaurus (N = 8; 75 ± 3 g) over a variety of submaximal intensities: 50%, 100% and 400% of the maximum aerobic speed (MAS = 0·27 m s−1; the speed at which V̇O2max is elicited). Activity duration was also varied (15, 60 and 300 s) over these intensities.
Total costs increased significantly with both activity intensity and duration. EPOC increased significantly with activity intensity. EPOC increased significantly with activity duration at higher intensities, but not the lowest intensity of 50% MAS.
These recovery costs constitute amounts of energy large enough to have an impact on energy budget analyses. The metabolic cost of an individual bout of activity and subsequent recovery was as high as 5% of the predicted daily energy expenditure, an increase of 5–8 × estimates that do not incorporate recovery.
To compare the relative economy of different activity regimens, the cost of activity (Cact; ml O2 g−1 km−1), was calculated as total costs, including EPOC, per unit distance travelled. Cact was independent of activity intensity over these ranges, but was inversely related to activity duration.
From these data, the most economical strategy to travel a certain distance would utilize a low‐intensity and extended duration, as seen in regular activities such as foraging. High‐intensity activities, such as escape, prey capture or mating behaviours, are thus predicted to be less economical. These should only be observed where metabolic costs would be considered secondary to the more proximal needs of the animal.
The effects of steady‐state erythromycin and azithromycin on the pharmacokinetics of sildenafil in healthy volunteers
Authors: Muirhead Gary J. , Faulkner Stephen , Harness Jane A. , Taubel Jörg 
Published: March 2003

Aims  Sildenafil, an effective oral treatment for erectile dysfunction, is predominantly metabolized by the cytochrome P450 isozyme 3A4, which is inhibited by a number of the macrolide antibiotics. Therefore, two placebo‐controlled, parallel‐group studies were conducted to evaluate the effects of multiple doses of erythromycin and azithromycin on the pharmacokinetics, safety and tolerability of a single oral 100‐mg dose of sildenafil.Methods  In the erythromycin interaction study, 26 male volunteers (18–45 years of age) received open‐label sildenafil 100 mg on day 1. Half received blinded erythromycin (500 mg) twice daily on days 2–6, and the other half received placebo. On day 6, all subjects received a second 100‐mg dose of sildenafil. In the azithromycin interaction study, 24 male volunteers (19–33 years of age) received open‐label 100 mg sildenafil on day 1. Half then received blinded azithromycin (500 mg) once daily on days 2–4, and the other half received placebo. On day 4, all subjects received another 100‐mg dose of sildenafil. In both studies, blood samples were collected on the first and last study day for the analysis of plasma concentrations of sildenafil and its primary metabolite, UK‐103,320.Results  Repeated dosing with erythromycin caused statistically significant increases in the AUC and Cmax of sildenafil (2.8‐fold and 2.6‐fold, respectively) but had no effect on Tmax, kel or t1/2. A statistically significant 1.4‐fold increase in the AUC of UK‐103,320 was also observed, as well as a significant decrease in kel, resulting in an increase of about 1 h in t1/2. In contrast, repeated dosing with azithromycin caused no significant change in any pharmacokinetic parameter of either sildenafil or UK‐103,320. Erythromycin, azithromycin and sildenafil were well tolerated; adverse events were mild and transient. No subject withdrew from either trial for any reason related to study drug.Conclusions  These results indicate that erythromycin modifies the pharmacokinetics of sildenafil by inhibiting its CYP3A4‐mediated first‐pass metabolism. Given these data, a lower starting dose of sildenafil (25 mg) may be considered for patients receiving erythromycin or other potent CYP3A4 inhibitors. Azithromycin did not affect the pharmacokinetics of sildenafil; therefore, no adjustment in dosage is necessary for patients receiving these drugs concomitantly.
Upper gastrointestinal bleeding among users of NSAIDs: a population‐based cohort study in Denmark
Authors: Mellemkjær Lene , Blot William J. , Sørensen Henrik Toft , Thomassen Lars , McLaughlin Joseph K. , Nielsen Gunnar Lauge , Olsen Jørgen H. 
Published: March 2003

Aims  It is well‐known that use of nonsteroidal anti‐inflammatory drugs (NSAIDs) increases the risk of upper gastrointestinal bleeding (UGIB), but characteristics of the association and quantification of excess risk at the population level require clarification.Methods  All users of nonaspirin prescription NSAIDs in North Jutland County, Denmark during 1991–95 were identified in the regional Pharmaco‐Epidemiologic Database. Using the Hospital Discharge Register, all hospitalizations for UGIBs were identified among the 156 138 users of NSAIDs and compared with the number of expected based on the North Jutland population who did not receive NSAID prescriptions.Results  During periods of NSAID use without use of other drugs associated with UGIB, we observed 365 UGIBs, a number 3.6 times higher than expected (95% CI = 3.3, 4.0). The excess risk varied by sex, type of NSAID and form and route of administration of the NSAID, but not by age at first NSAID prescription or number of prior prescriptions. Risk declined sharply following cessation of use. For ibuprofen and naproxen, there was a clear trend in rising risk by increasing dose, although the lowest doses were also associated with an excess of UGIB. Concurrent use of corticosteroids, anticoagulants and aspirin further increased the risk of UGIB.Conclusions  All types and formulations of NSAIDs appear to increase the risk of UGIBs, but the effect appear not to be cumulative and diminish rapidly with discontinue of use. Up to 15% of the UGIBs in the entire population of the North Jutland County may be explained by use of this drug.
Diurnal variation in the biliary excretion of flomoxef in patients with percutaneous transhepatic biliary drainage
Authors: Hishikawa Shuji , Kobayashi Eiji , Sugimoto Koh‐ichi , Miyata Michio , Fujimura Akio 
Published: March 2003

Aims  To examine diurnal variation in biliary excretion of flomoxef.Methods  Flomoxef (1 g) was injected intravenously in eight patients with percutaneous transhepatic cholangiography with drainage at 09.00 h and 21.00 h by a cross‐over design with a 36 h washout period. Drained biliary fluid was collected for 6 h after each dosing. These patients still had mild to moderate hepatic dysfunction.Results  Bile flow and bile acid excretion for 6 h after dosing did not differ significantly between the 09.00 h and 21.00 h treatments. The maximum concentration of biliary flomoxef was significantly greater and its total excretion for 6 h tended to be greater after the 21.00 h dose [maximum concentration (µg ml−1): 34.2 ± 29.9 (09.00 h dose) vs 43.5 ± 28.3 (21.00 h dose) (95% confidence interval for difference: 2.6∼15.9, P = 0.013); total excretion (mg 6 h−1): 1.4 ± 1.3 (09.00 h dose) vs 1.6 ± 1.2 (21.00 h dose) (95% confidence interval for difference: −26.8, 313.7, P = 0.087)]. The period that biliary flomoxef remained above the minimal inhibitory concentration did not differ significantly between the two treatment times.Conclusions  These results suggest that biliary excretion of flomoxef shows diurnal variation. However, as the difference was relatively small, flomoxef could be given at any time of day without any dosage adjustments.
A new laser pain threshold model detects a faster onset of action from a liquid formulation of 1 g paracetamol than an equivalent tablet formulation
Authors: Sutton J. A. , Gillin W. P. , Grattan T. J. , Clarke G. D. , Kilminster S. G. 
Published: March 2003

Aims  To discover whether a new infra‐red laser method could detect a change in pain threshold after as mild an analgesic as paracetamol and whether an effervescent liquid formulation produced a faster onset of action than tablets.
Methods
This double‐blind, placebo controlled randomized study used a portable, infra‐red laser to measure ‘first pain’ thresholds on the nondominant forearm in 12 normal volunteers before and after 1 g of paracetamol or placebo. The mean of six recordings was determined three times before dosing, the first being used as a familiarization procedure, and 14 times after dosing.
Results
We detected a small (2%), statistically significant difference in pain threshold between a liquid formulation of paracetamol and placebo at 30 and 60 min (P = 0.004 and P = 0.001), but not between tablets and placebo. Liquid also increased the threshold significantly compared with tablets at 60 min (P = 0.01).
Conclusions To detect such a small increase in pain threshold requires a highly consistent measure and the coefficient of variation was 2% for the study overall, surprisingly low for a subjective phenomenon. The reasons for this include minimizing reflectance by blacking the skin, using a nonhairy site, averaging six data points at each sample time and controlling closely the ambient conditions and the subjects' preparation for studies.
Sex and age differences in the pharmacokinetics of alosetron
Authors: Koch K. M. , Palmer J. L. , Noordin N. , Tomlinson J. J. , Baidoo C. 
Published: March 2003

Aims  To determine the effects of sex and age on the pharmacokinetics of alosetron.Methods  Single oral and intravenous 2 mg doses of alosetron were administered on separate occasions to 48 healthy, young and elderly, males and females. Serum was sampled for 12 h post‐dose to measure alosetron concentrations.Results  Serum concentrations of alosetron were higher in females than in males, resulting from a sex difference in clearance by metabolism. Mean clearance values were 504 vs 677 ml min−1 in young females vs males (mean ratio 0.75), and 461 vs 670 ml min−1 in elderly females vs males (mean ratio 0.69). The sex difference in alosetron pharmacokinetics achieved statistical significance in the elderly, but not in the young. Irrespective of sex, alosetron clearance was increased by smoking. Serum concentrations tended to be higher in the elderly, although the effect of age was generally not significant. Volume of distribution was smaller in females (approximately 63 l) compared with males (approximately 84 l), regardless of age or the sex difference in body weight.Conclusions  A significant difference in clearance by metabolism of alosetron between the sexes, and possibly between the young and elderly was observed.
A uniform regimen enables decentralized care of diabetic pregnancies
Authors: Vääräsmäki M. , Gissler M. , Hartikainen A.‐L. 
Published: March 2003

AbstractAims  A nationwide recommendation to standardize the care of diabetic pregnancies in different hospitals was given in Finland in 1993. The Medical Birth Register (MBR) was used to investigate whether these recommendations have been accepted and how they have affected the outcome of newborns.Methods  Data on 1442 singleton pregnancies complicated by insulin‐treated diabetes in 1991–1995 were obtained from the MBR.Results  The incidence of insulin treatment during pregnancy was 4.5 per 1000 births. Sixty‐six per cent (n = 954) of all women had Type 1 diabetes. During the study period, the number of deliveries managed in tertiary centres decreased from 59% to 47% (95% confidence interval [CI] 39–58%) and care was more often carried out on an out‐patient basis. The perinatal mortality rate (≥ 28 weeks of gestation) declined from 19.3 to 8.2/1000, being 12.6/1000 in the whole diabetic population and 5.5/1000 in the general population (95% CI 3.4–8.8/1000). The risk was especially increased in insulin‐treated gestational diabetic (GDM) pregnancies (14.3/1000). The proportion of macrosomic newborns (31.7%) in diabetic women was significantly higher than among the general population (3.2%) (95% CI 27.0–33.9%).Conclusions  The decentralization and change‐over to a mainly out‐patient basis of management does not appear to have increased the number of cases of adverse outcome of diabetic pregnancy when patients have been selected to the appropriate level of care. The risks in insulin‐treated GDM pregnancies were almost similar to Type 1 diabetes. To succeed, there must be a standardized care programme, continuous education and motivated personnel.Diabet. Med. 18, 871–876 (2001)
Do levels of immunoglobulin G antibodies to foods predict the development of immunoglobulin E antibodies to cat, dog and/or mite?
Authors: Eysink P. E. D. , Bindels P. J. E. , Stapel S. O. , Bottema B. J. A. M. , Van Der Zee J. S. , Aalberse R. C. 
Published: March 2003

SummaryBackground In children at high risk of inhalation allergy, food sensitization is associated with an increased risk for sensitization to inhalant allergens. Furthermore, this association was also found in a cross‐sectional study.Objective To examine in a prospective study, whether levels of IgG to foods (i.e. mixture of wheat and rice, mixture of soy bean and peanut, egg white, cow's milk, meat, orange and potato) indicate an increased risk for the future development of IgE antibodies to inhalant allergens in a low‐risk population and whether they can be used as predictors of the subsequent development of IgE antibodies in young, initially IgE‐negative children.Methods Coughing children, aged 1–5, visiting their GPs, were tested for IgE antibodies to mite, dog and cat (RAST) and IgG (ELISA) to foods. All IgE‐negative children were retested for IgE antibodies after two years. The IgG results (66 percentiles) of the first blood sample were compared to the RAST‐scores of the second blood sample.Results After two years, 51 out of 397 (12.8%) originally IgE‐negative children, had become IgE‐positive for cat, dog and/or mite. An increased IgG antibody level to wheat‐rice (OR = 2.2) and to orange (OR = 2.0) indicated an increased risk of developing IgE to cat, dog or mite allergens. In addition to IgG to a mixture of wheat‐rice and orange; total IgE, breastfeeding, eczema as a baby and age were the most important predictors for the subsequent development of IgE to inhalant allergens.Discussion An increased IgG antibody level to a mixture of wheat‐rice or orange, indicates an increased risk of developing IgE to cat, dog or mite allergens. This indicates that excessive activity of the mucosal immune system is present before IgE antibodies to airborne allergens can be demonstrated. Nevertheless, IgG to foods is not very helpful (with a positive predictive value of 16.5%, and negative predictive value of 90.6%) in identifying individual children at risk in clinical practice. However, besides other risk factors, IgG to wheat‐rice and to orange could be useful as a screening test for studies in the early identification, i.e. before IgE antibodies can be detected, of children with an increased risk of developing IgE antibodies in the future.
Specific monoclonal antibodies and human immunoglobulin E show that Hev b 5 is an abundant allergen in high protein powdered latex gloves
Authors: Sutherland M. F. , Drew A. , Rolland J. M. , Slater J. E. , Suphioglu C. , O'Hehir R. E. 
Published: March 2003

SummaryBackground  Hev b 5 is a major latex allergen recognized predominantly by latex‐allergic health care workers (HCWs). Recombinant Hev b 5 (rHev b 5) was previously expressed as a fusion protein with maltose binding protein (MBP), itself an immunogenic molecule; therefore non‐fusion rHev b 5 is desirable. Moreover, standardized immunological assays for the detection of Hev b 5 are currently lacking and may have important implications for both allergen avoidance and diagnosis in latex allergy.Objectives  To generate and use Hev b 5‐specific mAbs to determine the relative abundance of Hev b 5 in different latex extracts, correlating this with the IgE reactivity of latex‐allergic HCWs and to produce non‐fusion rHev b 5.Methods  For the production of mAbs, mice were immunized with rHev b 5/MBP fusion protein and mAbs selected with rHev b 5/MBP but not MBP reactivity. The mAb reactivity was compared with polyclonal IgE from latex‐allergic HCWs using direct and inhibition ELISA and immunoblot assays. Recombinant Hev b 5 was expressed and purified in the pPROEX‐HTa bacterial expression system.Results  Four Hev b 5‐specific mAbs were produced. Immunoblotting and ELISA using the mAbs indicate abundant Hev b 5 in high protein powdered latex glove extracts as compared with crude latex sap extracts. High quality surgical gloves with no detectable protein have no detectable Hev b 5. Inhibition ELISAs using serum IgE from latex‐allergic HCWs and Hev b 5‐specific mAbs gave strong correlation. Non‐fusion recombinant Hev b 5 was successfully expressed and purified, showing reactivity with both the Hev b 5‐specific mAbs and serum IgE of latex‐allergic HCWs.Conclusion  Hev b 5‐specific mAbs and human IgE from latex‐allergic HCWs demonstrate the greater content of Hev b 5 in high protein powdered glove extracts. This may explain the observed higher frequency of sensitization to this allergen in HCWs.
The human complement C9 gene: structural analysis of the 5′ gene region and genetic polymorphism studies
Authors: Witzel‐Schlömp K. , Rittner C. , Schneider P. M. 
Published: March 2003

SummaryC9 is the last of the human complement components creating the membrane attack complex. The single chain serum protein is encoded by a gene located on chromosome 5p13 that is composed of 11 exons. With the aid of inverse PCR, the hitherto unknown regions flanking exon 1 and the 3′ part of exon 11 (3′UTR) have been sequenced. A computer‐based analysis of the 300‐bp region located just upstream of the AUG start codon showed homologies to known DNA modules which affect the transcriptional regulation of certain genes. The most striking of these is a sequence that may substitute the missing TATA box in initiating C9 transcription. In the 3′UTR, three successive polyadenylation signals were found. Although the C9 protein is invariant, four different single nucleotide polymorphisms (SNPs) have been observed at the DNA level by exon‐specific PCR and direct sequencing. None of them changes the amino acid composition of the mature protein. Due to a C → T transition in exon 1 at cDNA position 17, the fifth amino acid of the leader peptide may be either an arginine or a tryptophane. Using either PCR/RFLP analysis (exons 1 and 11) or allele‐specific PCR (intron 1 and exon 4), each polymorphism can be characterized without sequencing. All of the exon 1, intron 1 and exon 11 variants could be detected in small population samples of European, Thai or South American Indian origin. In contrast, the exon 4 C variant was observed only once in a European. The first three SNPs can be combined to designate eight different ‘C9 alleles’. Of these, six have actually be found. These data provide strong evidence that several mutation and recombination events occurred in the course of C9 gene evolution.
Polymorphisms of tumour necrosis factors A and B in breast cancer
Authors: Park K. S. , Mok J. W. , Ko H. E. , Tokunaga K. , Lee M. H. 
Published: March 2003

SummaryWe assayed for germline single nucleotide polymorphisms (SNPs) in theTNFBandTNFAgenes in patients with breast cancer. SNPs were observed in the first intron ofTNFB(G/A) and at −1031 (T/C), −863 (C/A), −857 (C/T) and −308 (G/A) in the promoter region ofTNFAfrom peripheral leucocytes in 95 breast cancer patients and 190 healthy subjects as controls. TheTNFB*G/TNFB*Ghomozygote (23.2% vs. 5.8%,P= 0.001) was predominant in patients, while theTNFB*A/TNFB*Ahomozygote was less frequent in patients (34.7% vs. 46.3%,P = 0.041) than in the control subjects. Breast cancer was not associated with SNPs in theTNFApromoters. Although theTNFBSNP failed to associate with any clinicopathological parameter of breast cancer, a substantial difference in pathology among tumour stages for the −857 SNP inTNFAwas detected. These results indicate thatTNFBhas both tumorigenic and antitumorigenic capabilities depending on the genotype: theTNFBSNPTNFB*G/TNFB*Ggenotype gave an increased risk for breast cancer and that ofTNFB*A/TNFB*Agave resistance to breast cancer (OR = 5.3395%; CI: 2.33–12.19). The results suggest that theTNFB*Gallele plays some role in the tumorigenesis or activation of dormant tumour cells, but theTNFB*Aallele induces some function(s) leading to the inhibition of tumorigenesis.
Molecular analysis of HLA‐DRB1 polymorphism in north‐east Spain
Authors: Vidal S. , Morante M. P. , Moga E. , Mosquera A. M. , Querol S. , Garcia J. , Rodriguez‐Sanchez J. l. 
Published: March 2003

SummaryThe DRB1* polymorphism in 941 randomly selected individuals from the Umbilical Cord Blood Bank of Barcelona (92.75% of Spanish origin) was determined by sequence‐based typing. The HLA profile was similar to that of other Mediterranean populations, with DRB1*0701 and *0301 being the most frequent alleles. This may be a consequence of the mixture of alleles as a result of migration from contiguous geographical areas.