bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of photoperiod, temperature, and host plant age on induction of reproductive diapause and development time in Danaus plexippus
Authors: Goehring Liz , Oberhauser Karen S. 
Published: March 2003

Abstract 1. Diapause induction in monarch butterflies Danaus plexippus was studied using adults captured from the wild in Minnesota and Wisconsin, and individuals reared under outdoor and controlled conditions.2. Oocyte presence in females and ejaculatory duct mass in males were used to indicate reproductive status.3. Some wild individuals were in diapause in mid‐August, and all males and females were in diapause by late August and early September respectively.4. Individuals reared under decreasing day lengths and fluctuating temperatures were more likely to be in diapause than were individuals reared under long or short day lengths or constant temperatures.5. Individuals fed potted old Asclepias curassavica plants were more likely to be in diapause than were those fed potted young host plants; when cuttings of Asclepias syriaca plants from the field or greenhouse pots were used, there was no effect of host plant age.6. Extremely high temperatures increased the number of day‐degrees required for development from egg to adult, while decreasing day lengths and older host plants tended to decrease the number of day‐degrees required for development.7. There appears to be a continuum of reproductive development in monarchs, with gradual declines in mean ejaculatory duct mass and oocyte production during the late summer.8. None of the experimental treatments led to 100% diapause, and diapause was more likely to occur in monarchs subjected to more than one diapause‐inducing cue.
High‐altitude migration of the diamondback moth Plutella xylostella to the U.K.: a study using radar, aerial netting, and ground trapping
Authors: Chapman Jason W. , Reynolds Don R. , Smith Alan D. , Riley Joe R. , Pedgley David E. , Woiwod Ian P. 
Published: March 2003

Abstract 1. The high‐altitude wind‐borne migration of the diamondback moth Plutella xylostella in the U.K. in 2000 was investigated (a) by direct monitoring of insect flight by vertical‐looking radar and by aerial netting, and (b) through evidence of temporal variation in P. xylostella abundance deduced from a network of light traps.2. Migrating P. xylostella were identified by a unique combination of size and shape data derived from the continuously operating vertical‐looking radar.3. Radar‐detected migratory overflights correlated significantly with associated peaks in abundance of P. xylostella estimated by catches in a U.K.‐wide light trap network; however the correlation was stronger when light trap catches were lagged by 1 day.4. The first notable catches of P. xylostella in the U.K. occurred in early May, and were accompanied by migrations over the radar from the east.5. Radar data and back‐tracking indicated that a major wind‐borne migration of P. xylostella from The Netherlands to southern England took place in early May, and that this was responsible for the establishment of the U.K. population.6. The origin of early‐season P. xylostella occurring in Britain is discussed.
The response of smooth muscle cells to α‐thrombin depends on its arterial origin: comparison among different species
Authors: Varela  , Martínez‐González  , Badimon  
Published: March 2003

BackgroundThrombin plays a pivotal role in the pathogenesis of arterial thrombosis and exerts a wide spectrum of effects on the cells of vessel walls.MethodsIn this paper we focus on the direct role of thrombin as a mitogen for smooth muscle cells (SMCs) derived from different vessels from the vascular tree (coronary artery, aorta, carotid artery and pulmonary artery) of different species (human and pig). All cell populations examined responded mitogenically to α‐thrombin, however the extent of this response was dependent on both vascular origin and the species from which vessels were derived.ResultsThrombin (1–100 nmol L−1) induced DNA synthesis ranging from 1.5‐ to 4‐fold baseline depending on cell type. Porcine coronary SMCs showed the highest response to thrombin (100 nmol L−1) in terms of protein and DNA synthesis (4.0 ± 0.2‐fold) and cell division (53.4 ± 8.8%) among the tested cells. In these cells recombinant (r)‐hirudin, a specific thrombin inhibitor, exhibited maximal effectiveness to block the mitogenic effect of thrombin. Human SMC response ([3H]‐thymidine incorporation) to either sera or thrombin was lower than that of porcine cells. In contrast, c‐fos mRNA levels induced by thrombin in human SMCs were higher than those induced in porcine cells. In human cells, thrombin elicited an overexpression of c‐fos and a lower rate of [3H]‐thymidine incorporation than in porcine cells. Insulin‐like growth factor I but not insulin showed additive mitogenic effects with thrombin in human coronary SMCs. The response of these cells to thrombin from different sources was a function of thrombin specific activity.ConclusionThese results suggest that the cell system chosen to check thrombin mitogenicity not only determines thrombin quantitative effects but also may affect the effectiveness of an inhibitor to block its biological activity.
Accumulation of chylomicron remnants in homozygous subjects with familial hypercholesterolaemia
Authors: Mamo  , Smith  , Yu  , Kawaguchi  , Harada‐Shiba  , Yamamura  , Yamamoto  
Published: March 2003

BackgroundPost‐prandial lipoprotein kinetics were investigated in subjects who lack functioning low‐density lipoprotein (LDL) receptors [homozygous familial hypercholesterolaemia (FH)].MethodsAn oral fat load was given, and chylomicron plasma kinetics was determined by monitoring the clearance of triglyceride, retinyl palmitate and apolipoprotein B48, calculated as the area under the curve, for 7.5 h. In addition, the binding and uptake of chylomicron remnants by fibroblasts of FH and control subjects were assessed in vitro.ResultsBased on the plasma kinetics of chylomicron triglyceride, retinyl palmitate and apolipoprotein B48 after a lipid meal, chylomicron clearance was found to be substantially delayed compared with normolipidaemic control subjects. Consistent with involvement of the LDL receptor in chylomicron clearance, binding and uptake of chylomicron remnants by fibroblasts of FH subjects was found to be substantially less than in cells from control subjects.ConclusionThis study shows that, in addition to LDL, chylomicron metabolism is severely impaired in FH and that the LDL receptor is significantly involved in the clearance of post‐prandial lipoproteins. Moreover, this study raises the possibility that in FH, and in other disorders in which LDL receptor expression is reduced, atherogenesis might be a post‐prandial disease.
Expression of cGMP‐dependent protein kinase I and its substrate VASP in neointimal cells of the injured rat carotid artery
Authors: Mönks  , Lange  , Silber  , Markert  , Walter  , Nehls  
Published: March 2003

BackgroundNeointimal fibroproliferative lesions after balloon angioplasty remain a major clinical problem, frequently leading to restenosis of initially successfully dilated coronary arteries. The cGMP‐dependent protein kinase type I (cGMP‐PK I) and its substrate vasodilator‐stimulated phosphoprotein (VASP), molecular targets of the atrial natriuretic factor (ANF) and nitric oxide (NO) signalling pathways, are likely to be involved in various aspects of vascular wall regulation and restenosis formation.MethodsTo investigate the occurrence of cGMP‐PK I and VASP in neointimal cells in situ, we performed immunohistochemistry and immunoblotting experiments on denuded rat carotid arteries.ResultsAlthough the soluble cGMP‐PK I showed a homogeneous distribution throughout the neointima, VASP apparently was more concentrated in smooth muscle cells (SMCs) lining the artery lumen, possibly reflecting enhanced growth factor stimulation of luminal SMCs. The membrane‐associated cGMP‐PK type II could not be detected in both the non‐injured vessel wall and the restenotic tissue.ConclusionThe presence of both cGMP‐PK I and VASP, major regulators of the actin cytoskeleton and cell motility, in neointimal tissue suggest that this emerging signal transduction pathway could be a target for the regulation and control of restenosis.
Carbohydrate‐deficient transferrin is not a useful marker for the detection of chronic alcohol abuse
Authors: Schmitt  , Stieber  , Jüngst  , Bilzer  , Wächtler  , Heberger  , Seidel  
Published: March 2003

BackgroundThe role of carbohydrate‐deficient transferrin (CDT) as a reliable marker for the detection of chronic alcohol abuse has been discussed controversially.MethodsTherefore, we investigated CDT in the sera from 405 subjects with different alcohol intake. Besides healthy control subjects (n = 42), inpatients and outpatients in a department of gastroenterology (n = 325) and patients admitted to a department of otorhinolaryngology (n = 38) were studied. A total of 213 patients suffered from various forms of liver diseases, and 89 patients had liver transplantation. CDT values were determined by a double‐antibody radioimmunoassay.ResultsIn the 241 alcohol‐abstinent subjects, CDT levels ranged from 3 to 90 units L−1 (median = 12); the 92 moderate drinkers (20–60 g of alcohol per day) showed values from 3 to 40 units L−1 (median = 12), and the 72 subjects with chronic alcohol abuse (> 60 g per day) revealed CDT levels from 3 to 100 units L−1 (median = 16). The diagnostic specificity for alcohol abuse was 86.8% for men (sensitivity 36.9%) and 95% for women (sensitivity 0%).ConclusionOur data indicate that measurement of CDT does not reach clinical use in the detection of chronic alcohol abuse in an unselected population because of its insufficient specificity and sensitivity.
Relative hyperoxaluria, crystalluria and haematuria after megadose ingestion of vitamin C
Authors: Auer  , Auer  , Rodgers  
Published: March 2003

BackgroundLong‐term or high‐dosage consumption of vitamin C may play a role in calcium oxalate kidney stone formation. The present study was undertaken to determine the biochemical and physicochemical risk factors in a male subject who developed haematuria and calcium oxalate crystalluria after ingestion of large doses of ascorbic acid for 8 consecutive days.MethodsTwenty‐four‐hour urine samples were collected before and during the ascorbic acid ingestion period as well as after the detection of haematuria. A special procedure was implemented for urine collections to allow for oxalate, ascorbate and other urinalyses. Oxalate was determined in the presence of EDTA to prevent in vitro conversion to ascorbic acid, whereas ascorbate itself was determined by manual titration in a redox method using the dye dichlorophenolindophenol. Urinalysis data were used to compute calcium oxalate relative supersaturations and Tiselius risk indices, whereas scanning electron microscopy was used to examine urinary deposits.ResultsOxalate excretion increased by about 350% during ascorbate ingestion before haematuria. Ascorbate concentrations also increased dramatically but appeared to reach a plateau maximum. Increasing calcium excretion was accompanied by decreasing potassium and phosphate values. The calcium oxalate relative supersaturation and Tiselius risk index increased during vitamin C ingestion and large aggregates of calcium oxalate dihydrate crystals were observed by scanning electron microscopy immediately after the detection of haematuria.ConclusionHigh percentage metabolic conversion of ascorbate to oxalate in this subject caused relative hyperoxaluria and crystalluria, the latter manifesting itself as haematuria. Clinicians need to be alerted to the potential dangers of large dose ingestion of vitamin C in some individuals.
In vitro modulation of	L‐arginine transport in trophoblast cells by glucose
Authors: Eaton  , Sooranna  
Published: March 2003

BackgroundThe uptake of the semi–essential amino acid, L‐arginine, into trophoblast cells was measured with the aim of determining the effect of different glucose concentrations on
L‐arginine influx kinetics.MethodsThis study used a novel superfused microcarrier culture system of BeWo cells (an established choriocarcinoma cell line with many characteristics of normal human trophoblast) and a rapid, paired‐tracer dilution technique to measure unidirectional influx into the cells.ResultsAt 10 mmol L−1D‐glucose,
L‐arginine unidirectional influx across the microvillous border of the cells was saturable with a Km of 1.14 ± 0.14 mmol L−1 and a Vmax of 121.36 ± 5.89 nmol mg−1 protein min−1. When cells were preincubated for 24 h in the presence of 30 mmol L−1D‐glucose, there was a significant increase in the Vmax for
L‐arginine of nearly 30%. Similarly, preincubation in the presence of 1 mmol L−1D‐glucose and 12.5 mIU mL−1 human insulin reduced the Km for
L‐arginine influx by over 55%.ConclusionThese data suggest that the modulation of placental transport of L‐arginine by glucose and insulin could contribute to the fetal macrosomia observed in diabetic mothers.
The effect of circulating non‐esterified fatty acids on the entero‐insular axis
Authors: Ranganath  , Norris  , Morgan  , Wright  , Marks  
Published: March 2003

BackgroundCirculating non‐esterified fatty acids (NEFAs) have been causally associated with impairment of glucose metabolism, although their effect on the entero‐insular axis, either in obesity or health, is unknown.Materials and methodsGlucose, insulin, glucagon‐like peptide‐1 (7–36 amide) (GLP‐1) and glucose‐dependent insulinotropic polypeptide (GIP) responses to 100 g of carbohydrate in 400 mL water were evaluated during simultaneous modulation of circulating non‐esterified fatty acids (NEFAs). A total of 10 000 units of heparin (to increase serum NEFAs) and 500 mg of acipimox (2 h before oral carbohydrate ingestion to reduce serum NEFAs) were administered to seven obese [mean ± SEM: age 40 ± 3.7 years; body mass index (BMI) 38.9 ± 2.1 kg m−2] and seven lean (age 39.6 ± 3.6 years; BMI 22.4 ± 0.4 kg m−2) women.ResultsHigher fasting levels and post‐heparin total integrated NEFAs (P < 0.05) and glycerol (P < 0.05) responses were seen in the obese than in the lean group. Incremental integrated GLP‐1 responses to oral carbohydrate post‐heparin in lean (P < 0.01) and obese (P < 0.05) subjects were significantly lower than after acipimox. Total integrated GIP (P < 0.05) and glucose (P < 0.01) responses were higher post heparin than after acipimox in obese subjects only.ConclusionThe inverse relationship in GIP and GLP‐1 responses in the obese group after modulation of NEFAs indicates that reciprocal changes between these two hormones may exist to ensure constancy of B‐cell stimulation. Our results suggest that in obese subjects compensatory secretion of GIP was incomplete and could not prevent impairment in glucose tolerance after heparin‐induced rise in NEFAs. These results may be important in understanding the role of the insulinotropic hormones in carbohydrate metabolism characterized by high NEFA levels such as obesity and diabetes mellitus.
Relationship of Helicobacter pylori CagA(+) status to gastric juice vitamin C levels
Authors: Rokkas  , Liatsos  , Petridou  , Papatheodorou  , Karameris  , Ladas  , Raptis  
Published: March 2003

BackgroundTo date it is not known whether gastric juice vitamin C levels are influenced by Helicobacter pylori CagA(+) strains. The aim of the present study, therefore, was to study the impact of H. pylori CagA status on gastric juice vitamin C levels.Materials and methodsWe studied 30 H. pylori(+) patients, and the results were compared with 10 endoscopically and histologically normal H. pylori(−) subjects (control group) who were similar to the H. pylori(+) group in terms of age and sex. In all patients, gastric juice vitamin C levels were determined and the severity of gastritis was graded on a scale of 0 (absent) to 3 (severe). CagA was determined by immunoblotting the sera from patients against H. pylori antigens.ResultsAmong 30 H. pylori(+) patients, 20 were CagA(+) and 10 CagA(−). In the entire group of H. pylori(+) patients, the median gastric juice vitamin C levels (mg L−1) were 16.35 (range 3.5–33.6) and were significantly lower (P < 0.001) than in the control group of H. pylori(−) patients [35.5 (23.1–50.2)]. In addition, in the entire group of H. pylori(+) patients there was a highly significant (P < 0.0001) inverse correlation between the gastritis activity score and the gastric juice vitamin C levels. In the group of H. pylori CagA(+) patients, the median levels of gastric juice vitamin C were 13.8 (3.5–31.2) and were significantly lower than the corresponding levels in both the H. pylori CagA(−) group [24.8 (22–33.6), P < 0.01] and the H. pylori(−) control group [35.5 (23.1–50.2), P < 0.001], the last groups being similar. Furthermore, the gastritis activity median score in the H. pylori CagA(+) group [2 (1–3)] was significantly higher (P < 0.05) than in the H. pylori CagA(−) group [1 (1–2)].ConclusionThese data indicate that infection with CagA(+) H. pylori strains significantly lowers the gastric juice vitamin C levels in comparison with CagA(−) H. pylori strains, which might have a significant impact on gastric carcinogenesis.
Invasive aspergillosis in neutropenic patients: rapid neutrophil recovery is a risk factor for severe pulmonary complications
Authors: Todeschini  , Murari  , Bonesi  , Pizzolo  , Verlato  , Tecchio  , Meneghini  , Franchini  , Giuffrida  , Perona  , Bellavite  
Published: March 2003

BackgroundIn invasive aspergillosis, the duration of neutropenia is an accepted risk factor, and recovery from neutropenia is generally associated with a favourable outcome. However, the rapidity of granulocyte recovery may rarely be associated with adverse sequelae. The purpose of this study was to define the relationship between neutrophil (polymorphonuclear, PMN) recovery after chemotherapy‐induced bone marrow aplasia and the occurrence of severe pulmonary complications (haemoptysis, pneumothorax and death) in patients with haematological malignancies who developed invasive fungal pneumonias.MethodsTwenty consecutive patients were retrospectively studied; eight of them had developed pulmonary events between 5 and 11 days after neutrophil recovery that followed deep neutropenia (PMN < 100 μL−1).ResultsFive patients had haemoptysis (one of these also had pneumothorax) and three had pneumothorax. According to the multiplicative logistic model, the odds of occurrence of a pulmonary event increased significantly with increasing PMN count on the fifth day (P < 0.001). Five of the eight patients who had pulmonary complications died. Also, the risk of death was larger in the presence of rapid neutrophil recovery, although the difference was not statistically significant (P = 0.111). Analysis of clinical and laboratory data showed that the risk of pulmonary complications significantly increased when the neutrophil concentration was > 4500 μL−1 on day 5 after deep granulocyte neutropenia (PMN < 100 μL−1). There was no correlation between pulmonary complications, dosage of amphotericin B and deaths.ConclusionThe occurrence of life‐threatening complications in patients with invasive fungal pneumonia is closely related to rapid PMN recovery.
Microcirculation in venous ulcers and the surrounding skin: findings with capillary microscopy and a laser Doppler imager
Authors: Gschwandtner  , Ambrózy  , Fasching  , Willfort  , Schneider  , Böhler  , Gaggl  , Ehringer  
Published: March 2003

BackgroundTo obtain more information about microcirculatory disturbances in venous ulcers, we studied their laser Doppler flux images and capillary densities.Materials and methodsOn photographs of venous ulcers and the adjacent skin of 17 patients, four regions of interest were marked: one non‐granulation tissue area (NGTA) within the venous ulcer, one granulation tissue area (GTA) within the ulcer, one adjacent skin area (ASA) and one distant skin area (DSA). Within these four regions the average laser Doppler area fluxes and capillary densities were determined for each patient using a laser Doppler imager and capillary microscopy respectively.ResultsThe laser Doppler area flux (mean ± SD in AU) was significantly lower in NGTA (1.39 ± 1.12) than in GTA (4.06 ± 1.52) or DSA (3.86 ± 1.54) (P < 0.00001). In addition, the ASA flux (1.95 ± 1.39) was significantly lower than the GTA or DSA flux (P < 0.0001). Capillary density (capillaries per mm2) in NGTA (0.82 ± 1.98) was significantly lower than that in GTA (6.00 ± 2.55), ASA (13.88 ± 5.16) or DSA (10.29 ± 3.41) (P < 0.0001). In addition, the capillary density of ASA was significantly higher than that of GTA or DSA (P < 0.05).ConclusionThe four areas showed the following characteristics: NGTA, low laser Doppler area flux and lowest capillary density (possible sign of ulcer area without healing tendency); GTA, high laser Doppler area flux and second lowest capillary density (possible sign of wound healing); ASA, low laser Doppler area flux and highest capillary density (possible sign of healing process nearly completed; scar); DSA, high laser Doppler area flux and second highest number of capillaries (sign of microcirculation of chronic venous disorder).
Decreased vitamin A levels in common variable immunodeficiency: vitamin A supplementation in vivo enhances immunoglobulin production and downregulates inflammatory responses
Authors: Aukrust  , Müller  , Ueland  , Svardal  , Berge  , Frøland  
Published: March 2003

BackgroundVitamin A has a broad range of immunological effects, and vitamin A deficiency is associated with recurrent infections. Common variable immunodeficiency (CVI) is a group of B‐cell deficiency syndromes with impaired antibody production and recurrent bacterial infections as the major manifestations, but the immunological dysfunctions may also include T cells and macrophages. In the present study we examined the possible role of vitamin A deficiency in CVI.Patients and methodsWe analysed plasma vitamin A levels in 20 CVI patients and 16 controls, and examined the relationships between vitamin A and clinical, immunological and metabolic parameters in CVI. In the six CVI patients with the lowest vitamin A levels we also studied the effect of vitamin A supplementation in vivo on several immunological functions in these patients.Results(i) The majority of CVI patients had decreased vitamin A levels compared with healthy controls, as found in both cross‐sectional and longitudinal testing. (ii) Low vitamin A levels were associated with the occurrence of chronic bacterial infections and splenomegaly as well as high neopterin levels. Decreased levels of carrier protein and malabsorption were not observed. (iii) Vitamin A supplementation in patients with low vitamin A levels resulted in increased interleukin‐10 (IL‐10) and decreased tumour necrosis factor‐α (TNFα) levels, as found in both plasma and monocyte supernatants, possibly favouring anti‐inflammatory net effects. (iv) Vitamin A supplementation in vivo also enhanced anti‐CD40‐stimulated IgG production, serum IgA levels and phytohaemagglutinin (PHA)‐stimulated peripheral blood mononuclear cell (PBMC) proliferation.ConclusionA considerable subgroup of CVI patients appears to be characterized by low vitamin A levels. Our findings support a possible role for vitamin A supplementation in CVI, perhaps resulting in enhanced immunoglobulin synthesis and downregulated inflammatory responses.