bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cell cycle distribution of primitive haematopoietic cells stimulated in vitro and in vivo
Authors: Zhang X.‐W. , Audet J. , Piret J. M. , Li Y.‐X. 
Published: March 2003

Abstract.A novel approach is used to study the proliferating behaviour of primitive haematopoietic cell populations in response to different stimuli. A mathematical model based on the average proportion of apoptotic, dividing and quiescent cells in primitive haematopoietic cell populations is developed to describe the mitotic history of 5‐ (and 6‐) carboxyfluorescein diacetate succinimidyl ester‐labelled cells. The cell cycle distributions in different cytokine‐supplemented cultures of primitive human and mouse bone marrow cells are determined and compared with those found in vivo. The results indicate that a combination of flt‐3 ligand, Steel factor and interleukin‐11 or hyper‐interleukin‐6 provide a level of mitogenic stimulation similar to that existing in vivo after a myeloablative radiation dose. The comparison of the cell cycle distribution obtained for different cultures of human bone marrow CD34+(45RA/71)− cells demonstrates that the addition of flt‐3 ligand in these cultures decreases apoptosis significantly but does not reduce quiescence. In addition, in vivo and in vitro, it was found that more than 3 days of stimulation are required to recruit a maximum number of quiescent cells into active cell cycle. These kinetics of cell cycle activation are found to be similar to those identified for the haematopoietic stem cells compartment in the same cultures. This mathematical analysis provides a useful tool for the development of haematopoietic stem cell culture processes for clinical applications.
High sensitivity of human epidermal keratinocytes (HaCaT) to topoisomerase inhibitors
Authors: Pessina A. , Raimondi A. , Cerri A. , Piccirillo M. , Neri M. G. , Croera C. , Foti P. , Berti E. 
Published: March 2003

Abstract.In the panorama of the numerous established cell lines, the human keratinocyte line HaCaT has a very interesting feature, having a close similarity in functional competence to normal keratinocytes. This cell line has been used in many studies as a paradigm for epidermal cells and therefore we selected HaCaT as a cell model for investigating the activity of three antitopoisomerase drugs (Camptothecin, Doxorubicin, Ciprofloxacin) on in vitro cell growth. The effect was evaluated both by a 24‐h cytotoxicity test and by a 7‐day antiproliferation assay, in which the cell viability was assessed by an MTT (3‐(4,5‐dimethyl‐2‐thiazolyl) 2,5‐diphenil‐2‐H‐tetrazolium bromide) test. DNA topoisomerase I was also partially purified from a nuclear extract of HaCaT cells, the level of topo I catalytic activity was measured by a pBR322 DNA relaxation assay and then the in vitro effect of antitopoisomerase drugs on the target enzyme was also assessed.The results indicated that the in vitro sensitivity of human epidermal HaCaT cells to antitopoisomerase drugs is comparable to that of many human tumour cell lines. HaCaT cells express a high level of topoisomerase I activity that is significantly inhibited by both Camptothecin and Doxorubicin and to a minor degree by Ciprofloxacin. A high correlation between the cell sensitivity to the antitopoisomerase I drug measured by the MTT test and the in vitro direct inhibition of HaCaT topoisomerase I was observed, suggesting that HaCaT cells can represent a very interesting model both for studying cellular pharmacokinetics of antineoplastic drugs on keratinocytes and for predicting possible secondary effects, exerted by these drugs on cutaneous cells, during treatment with chemotherapy.
Ultrasonic scalpel in laparoscopic gynaecological surgery: an observational study in 354 cases
Authors: Jansen Frank W. , Trimbos‐Kemper Trudy , Baptist Trimbos J. 
Published: March 2003

AbstractObjective To evaluate the ultrasonically activated scalpel (UAS) and laparoscopic coagulating shears (LCS) for gynaecological laparoscopic procedures.Main outcome measures  Data were evaluated regarding type of procedure, duration of surgery, blood loss, complications and cost‐effectiveness of the technique.Design  Prospective observational study.Setting  All patients who underwent a laparoscopic procedure in which the UAS or LCS was used, between 1993 and 2001 at the Leiden University Medical Center.Results  A total of 354 consecutive women underwent a laparoscopic procedure with the UAS or LCS. One major complication occurred (bleeding) for which a laparotomy was necessary. The results showed that these instruments are effective tools for cutting and coagulating.Conclusions  Additionally to bipolar electrosurgery, the UAS is a safe instrument and is especially useful for extirpative laparoscopic procedures in gynaecology. Due to the cavitational effect, it is not, in our opinion, a good instrument for delicate reconstructive surgery for fertility.
Seasonality in surface‐layer net zooplankton communities in Prince William Sound, Alaska
Authors: Cooney R. T. , Coyle K. O. , Stockmar E. , Stark C. 
Published: March 2003

AbstractThe upper‐layer net‐zooplankton community in Prince William Sound, Alaska, is characterized by strong seasonality. Abundance and wet‐weight biomass in the upper 50 m drop to fewer than 100 individuals and 10 mg m−3 in February before rebounding to 5000 individuals and 600 mg m−3 in June. Copepods dominate in all months, but are augmented by other prominent taxa, particularly pteropods and larvaceans during the late spring, summer and fall. The small copepods Pseudocalanus, Acartia and Oithona are common. Though much less abundant, larger calanoids like Neocalanus, Calanus and Metridia contribute substantially to the biomass in spring and early summer. Meroplankters like barnacle nauplii are also occasionally very abundant. Neocalanus, Calanus and Pseudocalanus all exhibit ontogenetic vertical displacement of populations when stage 5 copepodites (C5) leave the surface in late May and early June for deep water. This seasonality has implications for food‐webs supporting juvenile pink salmon (Oncorhynchus gorbuscha) and Pacific herring (Clupea pallasi) in Prince William Sound.
Helicobacter pylori Eradication in Patients on Long‐ Term H2 Receptor Antagonists. Economic and Symptomatic Benefits. A Large Prospective Study in Primary Care
Authors: Verma Sumita , Giaffer Mustafa H. 
Published: March 2003

AbstractBackground. A large proportion of patients in primary care are still being maintained on long‐term acid suppression, without any attempts to identify Helicobacter pylori status and to treat those that test positive.Objectives. To assess the prevalence and economic and symptomatic benefits of H. pylori eradication in patients maintained on long‐term H2 receptor antagonists (H2RA) in primary care.Patients and Methods. Patients on long‐term (i.e. 6 months or longer) H2RA were identified from the computerised records of six practices in north England. Helicobacter pylori status was identified using serology and H. pylori positive patients were then offered standard 7‐day proton pump based triple therapy, followed by a urea breath test (UBT) to confirm H. pylori eradication. Those who had a positive UBT were offered a second line course of H. pylori eradication therapy. Follow up period was 1 year. The main outcome measures were improvement in dyspepsia symptom scores, amount of H2RA being consumed, and economic benefits after H. pylori eradication.Results. One thousand and seven patients (1.5%) were identified on long‐term H2RA, of whom 471 (46%) ultimately had their H. pylori serology assessed. Sixty‐three (297) percent of the patients tested had a positive serology for H. pylori, the majority of whom (58%, 172) had prior evidence of peptic ulcer disease. The mean duration of therapy and mean time since endoscopy/barium studies was significantly longer in patients with peptic ulcer disease compared to their counterparts with nonulcer dyspepsia and gastro‐oesophageal reflux disease, p= .0002 and .0001, respectively. After successful H. pylori eradication (which was possible in 84% of the patients), at the end of the 1‐year study period, on an intention to treat basis 62% of the patients could either stop or significantly reduce dosage of their H2RA. There was also significant reduction in the mean dose of H2RA being consumed and severity of symptoms at the end of the study period (p < .00001).Conclusion. Almost two‐thirds of patients on long‐term H2RA in primary care will have a positive serology for H. pylori; the majority of these will have peptic ulcer disease. In over 60% of cases H. pylori eradication led to significant improvement in symptom scores and reduction in dosage of H2RA being consumed. Cessation or reduction in long‐term H2RA prescribing is cost effective.
Quantitative study of the optic nerve in buffaloes (Bos bubalis)
Authors: KASSAB Ahmed , AOYAMA Masato , SUGITA Shoei 
Published: March 2003

ABSTRACTThe total number, distribution and size of the optic axons of the buffalo (Bos bubalis) were studied in five optic nerves using light and transmission electron microscopes. Semithin sections were cut at 0.40 μm with an ultramicrotome and stained with 0.3% toluidine blue for light microscopic analysis. The ultrathin sections were cut at 70 nm, mounted on copper mesh grids (No. 200) and stained with saturated solution of uranyl acetate dihydrate and examined with the transmission electron microscope. The optic axons were assessed in 10 regions of roughly equal area. The total number of optic fibers was estimated on semithin and ultrathin sections. The measurements of the axonal diameters were made on electron micrographs taken from various regions across the optic nerve. The mean value of the total number of optic axons calculated was 1 397 099 ± 10 995 and 1 584 255 by light and electron microscopes, respectively. There was very little difference in the density of the optic fibers between the 10 regions of the optic nerve. The optic nerve area ranged from 18.2 to 22.4 mm2 (mean, 21.3 mm2). The diameters of the optic axons ranged from 0.5 to 12.3 μm (mean, 3.3 μm).
Dietary conjugated linoleic acids alleviate early inflammatory response caused by lipopolysaccharide injection in male broiler chicks
Authors: TAKAHASHI Kazuaki , AKIBA Yukio , IWATA Toshio , KASAI Masaaki 
Published: March 2003

ABSTRACTAn experiment was undertaken to determine if dietary conjugated linoleic acid (CLA) influences the early stage of the inflammatory response caused by a single injection of Salmonella enteritidisi lipopolysaccharide (LPS) in male broiler chicks. Chicks (7 days old) were fed either 0 or 10 g CLA/kg in their diet for 21 days. At 28 days old, birds were injected intraperitoneally with 1.5 mg LPS/kg body weight after 12 h fasting. Changes in feed intake, rectal temperature and plasma α‐1 acid glycoprotein and ceruloplasmin concentrations were measured during 24 h after LPS injection. Chicks fed the CLA diet were fed more feed for 24 h, had a lower rectal temperature at 9 and 24 h and a lower plasma α‐1 acid glycoprotein concentration at 24 h after LPS injection than chicks fed the basal diet. Plasma ceruloplasmin concentration tended to be lower in chicks fed the CLA diet than in chicks fed the basal diet. The results suggest that dietary CLA alleviate undesirable early inflammatory response due to LPS injection in male broiler chicks.
Effect of ruminal dosing of mechanical stimulating brush on carcass characteristics and fatty acid composition of dressed carcass fat in fattening Holstein steers fed with high‐concentrate diets
Authors: HORIGUCHI Ken‐ichi , TAKAHASHI Toshiyoshi 
Published: March 2003

ABSTRACTThis experiment was undertaken to examine the effect of dosing of a mechanical stimulating brush (RF) in the rumen on dressed carcass characteristics and on the fatty acid composition of dressed carcass fat in fattening beef cattle. The fattening trial was carried out with high‐concentrate diets (organic cell wall contents: 27.5% on a dry mater basis) in eight Holstein steers (12 months of age). Four of the experimental animals were orally dosed with three RF/head (RF group); the other four animals without RF dosing were allotted as the control group. Grass hay was fed to the animals (0.2 kg/head/day) until 19 months of age. Concentrate diet was given ad libitum during the experiment. There were no statistical differences between the RF group and the control group in yield score and meat quality score of dressed carcass characteristics. Regarding fatty acid composition of dressed carcass fat, the proportion of C18 : 2 fatty acids in subcutaneous fat in the RF group was greater (P < 0.05) than that in the control group. C16 : 0 fatty acids in kidney fat in the RF group was lower (P < 0.05), and C18 : 2 fatty acids and total unsaturated fatty acids of 18 carbon number in kidney fat in the RF group were higher (P < 0.05) compared with the control group. The proportion of C18 : 2 fatty acids in rib eye fat in the RF group was greater (P < 0.05) than that in the control group. C18 : 1 fatty acids, C18 : 2 fatty acids and total unsaturated fatty acids of 18 carbon number in rib fat in the RF group were greater (P < 0.05) than those in the control group. The results suggest that in fattening Holstein steers fed with high‐concentrate diets, the effect of ruminal RF dosing on dressed carcass characteristics is not significant, but the proportion of unsaturated fatty acid of carcass fat is increased.
The role of land plants, phosphorus weathering and fire in the rise and regulation of atmospheric oxygen
Authors: Lenton Timothy M. 
Published: March 2003

AbstractThe evolution of vascular plants and their spread across the land surface, beginning ∼420 Ma, progressively increased the rate of weathering of phosphorus from rocks. This phosphorus supply promoted terrestrial and marine productivity and the burial of organic carbon, which has been the major source of O2 over geological timescales. Hence, it is predicted that the rise of plants led to an increase in the O2 content of the atmosphere from ∼12 vol %, 570–400 Ma to its present level of ∼21 vol % by ∼340 Ma. Previous modelling studies suggest that O2 then rose to ∼35 vol % ∼300 Ma. Such high concentrations are difficult to reconcile with the known persistence of forests, because rising O2 increases the frequency and intensity of vegetation fires, tending to decrease biomass and cause ecological shifts toward faster regenerating ecosystems. Rising O2 also directly inhibits C3 photosynthetic carbon assimilation and increases the production of toxic reactive oxygen species in cells. These effects suppress plant‐induced phosphorus weathering and hence organic carbon burial, providing a sensitive negative feedback on O2. A revised model predicts that this mechanism could have regulated atmospheric O2 within the range 15–25 vol % for the last 350 million years.
Isolation and characterization of a new nucleolar protein, Nrap, that is conserved from yeast to humans
Authors: Utama Budi , Kennedy Derek , Ru Kelin , Mattick John S. 
Published: March 2003

AbstractBackground: The nucleolus is the site of rRNA synthesis and processing in eukaryotic cells, but its composition remains poorly understood.Results: We have identified a novel nucleolar RNA‐associated protein (Nrap) which is highly conserved from yeast (Saccharomyces cerevisiae) to human, with homologues in mouse, Drosophila melanogaster, Caenorhabditis elegans, Arabidopsis thaliana, Schizosaccharomyces pombe, and other species. In the mouse, we have found that Nrap is ubiquitously expressed and is specifically localized in the nucleolus. We have also identified splice variants in human and mouse, and defined the intron‐exon structure of the human Nrap gene. Nrap is inherited into daughter nuclei by associating with the condensed chromosomes during mitosis. RNase treatment of permeabilized cells indicated that the nucleolar localization of Nrap is RNA dependent. The effects of actinomycin D, cycloheximide and 5,6‐dichloro‐β‐d‐ribofuranosyl‐benzimidazole on Nrap expression and distribution in cultured cells suggest that Nrap is associated with the pre‐rRNA transcript.Conclusions: Nrap is a large nucleolar protein (of more than 1000 amino acids), and is a new class of protein with new structural and functional motifs. Nrap appears to be associated with ribosome biogenesis by interacting with pre‐rRNA primary transcript.
Resistance training increases glucose uptake and transport in rat skeletal muscle
Authors: Yaspelkis B. B. , Singh M. K. , Trevino B. , Krisan A. D. , Collins D. E. 
Published: March 2003

ABSTRACTThe aim of this investigation was to determine if resistance training exercise improved glucose uptake and transport in rodent skeletal muscle. Sprague–Dawley rats were assigned to one of the three groups: control (CON), resistance trained (RT) and aerobic exercise trained (AT). Resistance trained rats were placed in a rodent squat apparatus and performed three sets of 10 repetitions at 75% of their one repetition maximum 3 days week−1 for 12 weeks. Aerobic exercise training consisted of running the rats 3 days week−1 for 45 min over a 12‐week period on a motor‐driven treadmill (32 m min−1, 15% grade). Following the training period, all animals were subjected to hind limb perfusion in the presence of 500 μU mL−1 insulin. Hind limb glucose uptake was similar in the RT (9.91 ± 0.7 μmol g−1 h−1) and AT (10.23 ± 1.0 μmol g−1 h−1) animals and significantly greater than control (CON) (6.40 ± 0.6 μmol g−1 h−1). Rates of 3‐O‐methyl‐d‐glucose transport in the RT animals were elevated in the muscles utilized for RT while in the AT animals rates of 3‐O‐methyl‐d‐glucose transport were increased in those muscles recruited for running. The increased rates of 3‐O‐methyl‐d‐glucose transport in the skeletal muscles of the resistance trained and aerobic exercise trained animals appeared to be, in part, because of an increased GLUT4 protein concentration. These findings suggest that both resistance or aerobic training exercise can improve insulin‐stimulated skeletal muscle glucose uptake and transport, but the training adaptations are restricted to the muscles recruited for the exercise performance.
Lithium and KB‐R7943 effects on mechanics and energetics of rat heart muscle
Authors: Bonazzola P. , Egido P. , Marengo F. D. , Savio‐Galimberti E. , Ponce‐Hornos J. E. 
Published: March 2003

ABSTRACTThe role of calcium influx on energy expenditure during cardiac contraction was studied. For this purpose, the described ability of lithium and KB‐R 7943 (KBR) to diminish Ca entry through Na–Ca exchanger (Ponce‐Hornos & Langer, J Mol Cell Cardiol 1980, 12, 1367, Satoh et al., Circulation 2000, 101, 1441) were used. In isolated contractions (contractions elicited after at least 5 min of rest) LiCl 45 mmol L−1 decreased pressure developed and pressure–time integral from 42.3 ± 2.7 and 14.5 ± 1.2 to 32.1 ± 3.4 mN mm−2 and 8.3 ± 0.9 mN mm−2 s, respectively. A similar effect was observed in regular contractions (at 0.16 Hz stimulation). The presence of KBR (5 μmol L−1) in the perfusate induced a slight but not significant decrease in pressure developed and pressure–time integral in steady‐state contractions. As it was previously described, the heat involved in a heart muscle contraction can be decomposed into several components (H1, H2, H3 and H4), but only one (H3) was associated with force generation. While H3 decreased with lithium in both types of contractions, H3/PtI ratio remained unaltered, indicating that the economy for pressure maintenance was unaffected. To further investigate the role of Ca entry on force development, a condition in which the contraction is mainly dependent on extracellular calcium was studied. An ‘extra’ stimulus applied 200 ms after the regular one in a muscle stimulated at 0.16 Hz induces a contraction with this characteristic (Marengo et al., Am J Physiol 1999, 276, H309). Lithium induced a strong decrease in pressure–time integral and H3 associated with this contraction (43 and 45%, respectively) with no change in H3/PtI ratio. Lithium also reduced (53%) an energy component (H2) associated with Ca cycling. The use of KBR showed qualitatively similar results [i.e. a 33% reduction in pressure–time integral associated with the extrasystole (ES) with no changes in H3/PtI ratio and a 30% reduction in the H2 component]. Li and KBR effects appear to be additive and in the presence of 45 mmol L−1 Li and 5 μmol L−1 KBR the extrasystole was abolished in 77%. Lithium and KBR effects particularly for the extrasystole can be explained through the inhibition of Ca entry via Na–Ca exchange giving support to the participation of the Na–Ca exchanger in the Ca influx from the extracellular space. In addition, the results also suggest the possibility of an effect of Li on an additional Ca sensitive locus (different than the Na–Ca exchanger). In this connection, in isolated contractions lithium decreased the energy release fraction related to mitochondrial processes (H4) increasing the economy of the overall cardiac contraction.
Cardiovascular responses to angiotensin II in atherosclerosis
Authors: Wilfert K. , Guski H. , Persson P. B. , Stauss H. M. 
Published: March 2003

ABSTRACTAtherosclerosis is associated with increased angiotensin II AT1‐receptor expression and vascular hyperresponsiveness to angiotensin II. Nevertheless, atherosclerosis is often not accompanied by hypertension. We studied if the hypertensive effect of angiotensin II is more pronounced in atherosclerosis. Rabbits were fed a high‐cholesterol diet (n = 10) for 12 weeks, followed by a standard diet for another 6 weeks. Control animals received the standard diet (n = 8) for 18 weeks. After 18 weeks, haemodynamic measurements were performed during a baseline recording and during an intravenous infusion of angiotensin II (0.4 μg kg−1 min−1). Atherosclerosis in the high‐cholesterol group was verified by histological and lipidchemical tissue examinations. During angiotensin II infusion, total peripheral resistance (TPR) increased more in the high‐cholesterol group than in controls (+81.6 ± 12.4 vs. +40.6 ± 9.7 mmHg min L−1, P < 0.05). While cardiac output and stroke volume (SV) decreased more in the high‐cholesterol group (P < 0.05), reflex bradycardia was stronger in the control group (P < 0.05), indicating a reduced baroreceptor reflex sensitivity in atherosclerosis. Despite the larger increase in TPR and the reduced baroreceptor reflex sensitivity in the high‐cholesterol group, maximum blood pressure response to angiotensin II was similar in both groups. The lack of a greater blood pressure response to angiotensin II in the high‐cholesterol group could be the result of the early stages of heart failure. Under resting conditions, heart failure seems to be fully compensated, as baseline haemodynamic parameters were similar in the high‐cholesterol group and in controls. However, during angiotensin II infusion, the compensatory mechanisms do not prevent a stronger fall in cardiac output and SV. Therefore, the blood pressure response to angiotensin II is not exaggerated in atherosclerotic animals, as vascular hyperresponsiveness to angiotensin II is opposed by the stronger fall in cardiac output and SV.