bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ventilatory capacity and exercise tolerance in patients with chronic stable heart failure
Authors: Clark Andrew L. , Davies L. Ceri , Francis Darrel P. , Coats Andrew J.S. 
Published: July 2002

AbstractBackgroundPatients with chronic heart failure complain of breathlessness. This is associated with an increase in the ventilatory response to carbon dioxide production (Ve/Vco2 slope), yet a reduction in the maximal ventilation achieved at peak exercise. We analysed ventilatory capacity in heart failure in relation to exercise capacity.MethodsWe analysed data from 74 patients with chronic stable heart failure [age (S.D.) 50.6 (8.8) years; left ventricular ejection fraction 30 (15)%] and 36 controls [48.9 (11.5) years]. Subjects undertook maximal incremental exercise testing with metabolic gas exchange measurements to derive peak oxygen consumption (Vo2), the Ve/Vco2 slope and ventilation. Spirometry was used to measure FEV1 and FVC. Maximal voluntary ventilation (MVV) was calculated as FEV1×35.ResultsPeak Vo2 was lower in patients [20.9 (7.5) ml min−1 kg−1 vs. 34.5 (10.1); P<0.001] and Ve/Vco2 greater [33.4 (10.7) vs. 26.0 (4.7); P<0.001]. Ventilation at peak exercise was lower in patients [63.5 (20.4) l/min vs. 86.9 (29.5); P<0.001], as was MVV [110.1 (37.9) l/min vs. 136.2 (53.1); P<0.001], but ventilation at peak as a proportion of MVV was the same in patients [60.0 (19.0)%] as controls [65.7 (12.4)%)]. There was an inverse relation between peak Vo2 and Ve/Vco2 slope (r=−0.62; P<0.001). Percentage predicted FEV1 correlated with ventilation at peak (r=0.62; P<0.001) and inversely with Ve/Vco2 slope (r=−0.32; P<0.001). There was no relation between percentage of MVV achieved and peak Vo2, or Ve/Vco2 slope.ConclusionsAlthough ventilation at peak exercise is lower in patients with heart failure than normal subjects, ventilation is the same proportion of maximal voluntary ventilation. These findings suggest that ventilatory capacity does not limit exercise capacity in heart failure.
Management of heart failure in Switzerland
Authors: Muntwyler Jörg , Follath Ferenc 
Published: July 2002

AbstractSimilar to other countries, heart failure is a major cause of morbidity and mortality in Switzerland. Among heart failure patients admitted to a Swiss university hospital in 1998, admission therapy included: ACE inhibitors/AT‐II blockers in approximately two‐thirds; diuretics in approximately 70%; and beta‐blockers in approximately one‐third. Easy access to diagnostic tests and limited results of surveys suggest that quality of care of heart failure patients is satisfactory in Switzerland. However, results from ongoing studies are required to assess more reliably the quality of diagnosis and therapy of this high‐risk population in Switzerland.
Direct Measurement of pH Profiles in Immobilized Enzyme Carriers during Kinetically Controlled Synthesis Using CLSM
Authors: Spiess Antje C. , Kasche Volker 
Published: July 2002

AbstractConfocal laser scanning microscopy was applied to measure the pH value in the carrier of immobilized enzymes during the enzyme‐catalyzed synthesis. pH profiles with a high resolution are shown, with the pH increasing in the core of the particles. Significant differences occur for different carrier material, particle size, porosity and surface modification. The increased pH value is identified as one of the reasons leading to reduced enzyme selectivity in the penicillin amidase catalyzed synthesis of cephalosporins and penicillins.
Control and Fault Diagnosis in Bottom Fermentation Systems Using Parity Space Approach
Authors: Riverol C. , Pilipovik M. V. 
Published: July 2002

AbstractThe main objective of this note is to describe a real‐time fault diagnosis and control for a cylindroconical fermenter to laboratory scale as an alternative to the classic systems. Development of a good controller for a fed‐batch reactor is not enough without a fault diagnosis system. We are working to expand this idea. The failure detection system is based on the parity space approach joined with a fuzzy controller with more robustness and of superior performance in MIMO systems compared to conventional strategies. A 2‐week period is reported.
Effect of Oxygen Limitation on β‐Lactamase Production
Authors: Sargantanis Ioannis G. , Karim M. N. 
Published: July 2002

AbstractThe dissolved oxygen concentration (DO) is an important variable in aerobic fermentations. Precise control of the DO is critical in fermentation processes for the investigation of the best conditions for secondary product formation. Oxygen limitation conditions have been known to enhance the synthesis of secondary products. An adaptive pole placement control that maintains a constant sheer environment is applied to Bacillus subtilis fermentation for the production of β‐lactamase. Auto Regressive eXogeneous (ARX) input models are used for the control, and supervision and coordination techniques are applied to improve the control performance. The effect of DO level on the productivity of β‐lactamase under oxygen‐limited conditions is assessed.
Parameters Affecting the Efficiency of Affinity‐Based Reversed Micellar Extraction and Separation (ARMES) in Glycoprotein Purification
Authors: Choe Jaehoon , VanderNoot Victoria A. , Linhardt Robert J. , Dordick Jonathan S. 
Published: July 2002

AbstractAffinity‐based reversed micellar extraction and separation (ARMES) is an effective method for purifying both low and high molecular weight glycoproteins via liquid‐liquid extraction. A range of extraction conditions were examined to gain insight into the mechanism of ARMES. Concanavalin A (Con A) was used as the model affinity ligand to bind soybean peroxidase (SBP) and β‐galactosidase as model glycoproteins. Factorial design was used to investigate the effect of various system variables on the extraction of SBP via ARMES. A quadratic model described the system well, resulting in a standard deviation of 7% between calculated and experimental extraction efficiencies. Sensitivity analysis suggested that the key criteria in ARMES were the NaCl concentration and pH of the aqueous feed phase. Extraction of both glycoproteins decreased above pH 7 but fell to zero only at pH values significantly above the pI of the model glycoproteins and the Con A affinity ligand. It is proposed that the complex of the affinity lectin with the glycoprotein results in a sufficiently hydrophobic species that can be extracted into a reversed micellar organic phase even at pH's far above the pI's of the individual proteins that comprise the complex. This finding has practical considerations for the use of ARMES in the resolution and purification of protein glycoforms.
Reactor Design Issues for Synthesis‐Gas Fermentations
Authors: Bredwell Marshall D. , Srivastava Prashant , Worden R. Mark 
Published: July 2002

AbstractSynthesis gas is readily obtained by gasifying coal, oil, biomass, or waste organics and represents an abundant, potentially inexpensive, feedstock for bioprocessing. The primary components of synthesis gas, carbon monoxide and hydrogen, can be converted into methane, organic acids, and alcohols via anaerobic fermentations. Bioconversion of synthesis gas is an attractive alternative to catalytic processing because the biological catalysts are highly specific and often more tolerant of sulfur contaminants than inorganic catalysts. However, because the aqueous solubilities of carbon monoxide and hydrogen are low, synthesis‐gas fermentations are typically limited by the rate of gas‐to‐liquid mass transfer. Consequently, a major engineering challenge in commercial development of synthesis‐gas fermentations is to provide sufficient gas mass transfer in an energy‐efficient manner. This paper reviews recent progress in the development of synthesis‐gas fermentations, with emphasis on efforts to increase the efficiency of gas mass transfer. Metabolic properties of several microbes able to ferment synthesis gas are described. Results of synthesis‐gas fermentations conducted in various bioreactor configurations are summarized. Recent results showing enhancement of synthesis‐gas fermentations using microbubble dispersions are presented, and studies of the mass‐transfer and coalescence properties of microbubbles are described.
Absence of the psbH gene product destabilizes photosystem II complex and bicarbonate binding on its acceptor side in Synechocystis PCC 6803
Authors: Komenda Josef , Lupínková Lenka , Kopecký Jiří 
Published: July 2002

The PsbH protein, a small subunit of the photosystem II complex (PSII), was identified as a 6‐kDa protein band in the PSII core and subcore (CP47–D1–D2–cyt b‐559) from the wild‐type strain of the cyanobacterium Synechocystis PCC 6803. The protein was missing in the D1–D2–cytochrome b‐559 complex and also in all PSII complexes isolated from IC7, a mutant lacking the psbH gene. The following properties of PSII in the mutant contrasted with those in wild‐type: (a) CP47 was released during nondenaturing electrophoresis of the PSII core isolated from IC7;	(b) depletion of CO2 resulted in a reversible decrease of the␣ reoxidation rate in the IC7 cells; (c) light‐induced decrease in PSII activity, measured as 2,5–dimethyl‐benzoquinone‐supported Hill reaction, was strongly dependent on the HCO3– concentration in the IC7 cells; and (d) illumination of the IC7 cells lead to an extensive oxidation, fragmentation and cross‐linking of the D1 protein. We did not find any evidence for phosphorylation of the PsbH protein in the wild‐type strain. The results showed that in the PSII complex of Synechocystis attachment of CP47 to the D1–D2 heterodimer appears weakened and binding of bicarbonate on the PSII acceptor side is destabilized in the absence of the PsbH protein.
The effects of moclobemide on the pharmacokinetics of the 5‐HT1B/1D agonist rizatriptan in healthy volunteers
Authors: Van Haarst A. D. , Van Gerven J. M. A. , Cohen A. F. , De Smet M. , Sterrett A. , Birk K. L. , Fisher A. L. , De Puy M. E. , Goldberg M. R. , Musson D. G. 
Published: July 2002

Aims
The new 5‐HT1B/1D agonist rizatriptan (MK‐0462) has recently been registered for the treatment of migraine. Its primary route of metabolism is via monoamine oxidase‐A (MAO‐A). Antidepressants such as the MAO‐A inhibitor moclobemide may be used in patients with chronic headache syndromes. Hence, this study aimed to investigate the interactions between rizatriptan and moclobemide.
Methods
In a double‐blind, randomized, placebo‐controlled, two‐period cross‐over study 12 healthy, young volunteers (six males, six females) were treated with moclobemide (150 mg twice daily) or placebo for 4 days. On the fourth day, a single dose of rizatriptan (10 mg) was administered, and subsequently blood and urine samples were collected for assay of rizatripan and N‐monodesmethyl rizatriptan. Plasma concentrates of 3,4‐dihydroxyphenylglycol (DHPG), a marker of MAO‐A inhibition, were also assessed. Supine and standing blood pressure were measured regularly.
Results
Both treatments were well tolerated. During moclobemide, the increase in supine diastolic blood pressure following rizatriptan administration was augmented. Inhibition of MAO by moclobemide was inferred from a persistent decrease in DHPG level (43% on average). When rizatriptan was coadministered with moclobemide, the area under the plasma drug concentration‐time profiles for rizatriptan and its N‐monodesmethyl metabolite increased 2.2‐fold (90% CI, 1.93–2.47) and 5.3‐fold (90% CI, 4.81–5.91), respectively, when compared with placebo. Peak plasma drug concentrations for rizatriptan and its n‐monodesmethyl metabolite increased 1.4‐fold (90% CI, 1.11–1.80) and 2.6‐fold (90% CI, 2.23–3.14), respectively, and half‐lives of both were prolonged.
Conclusions
Moclobemide inhibited the metabolism of rizatriptan and its active N‐monodesmethyl metabolite through inhibition of MAO‐A. Thus, moclobemide may considerably potentiate rizatriptan action. Concurrent administration of moclobemide and rizatriptan is not recommended.
Bone mineral density and markers of bone turnover in young adult survivors of childhood lymphoblastic leukaemia
Authors: Hoorweg‐Nijman Jantine J. G. , Kardos Gabriella , Roos Jan C. , van Dijk Henrika J. , Netelenbos Coen , Popp‐Snijders Corrie , de Ridder Christine M. , Delemarre‐van de Waal Henriëtte A. 
Published: July 2002

OBJECTIVEIn order to determine if a serious disease like childhood acute lymphoblastic leukaemia (ALL) and the treatment necessary to cure the patients has long term effects on bone mass, we assessed bone mineral density (BMD) and several parameters involved in bone formation in a group of young adult survivors of ALL.DESIGN AND PATIENTSFourteen male and ten female survivors, treated for ALL in childhood, were cross‐sectionally studied, at a mean age of 25.1 years (range 20.1–34.9). All patients, except for two, had received cranial irradiation as part of their treatment (mean radiation dose 2460 cGy).MEASUREMENTSHeight and weight were measured. Bone mineral density (BMD) was assessed using dual energy X‐ray absorptiometry in the lumbar spine, femoral neck, femoral trochanter and at 1/3 distal and ultradistal in the radius. Early morning serum levels of LH, FSH, oestradiol or testosterone, IGF‐1 and IGF‐BP3 were determined as well as several specific markers of bone turnover.RESULTSMean height, expressed as standard deviation score (SDS) was −1.12, significantly reduced. BMD in the lumbar spine, femoral neck and at 1/3 distal and ultradistal in the radius, was significantly lower compared to the reference population (P < 0.05). No correlation was found between the BMD values and the cumulative dose of administered cytotoxic drugs, the age at diagnosis of ALL or the duration of follow‐up. Mean IGF‐1 and IGF‐BP3 SDS‐scores were −1.24 and −0.78 respectively, significantly reduced. GH stimulation tests performed in a subgroup of 9 patients showed an insufficient peak GH response in at least one test in all tested patients. The values of LH, FSH oestradiol or testosterone were within the normal adult range. Serum markers of bone formation and bone resorption were in the normal range, indicating that bone turnover was normal at the time of the study.CONCLUSIONSBone development in patients cured of acute lymphoblastic leukaemia is disturbed, resulting in a significantly reduced bone mineral density. Impaired growth hormone activity, as a long term effect of cranial irradiation, may be one of the underlying causes as well as the illness itself and the administered cytotoxic drugs. Since a reduced bone mineral density predispose patients to osteoporosis, intervention in order to improve bone mass should be considered.
Suppression of endogenous insulin secretion by exogenous insulin in patients with insulinoma
Authors: Kim Chul‐Hee , Park Joong , Shong Young , Hong Sung , Kim Ghi , Lee Ki‐Up 
Published: July 2002

OBJECTIVEPrevious studies have demonstrated that endogenous insulin secretion is not suppressed by exogenous insulin in patients with insulinoma. In this study we examined whether insulin secretion in insulinoma patients is suppressed by exogenous insulin during hypoglycaemia.SUBJECTS AND METHODSSixteen insulinoma patients (5 men and 11 women) and 10 normal subjects were studied. Hyperinsulinaemic glucose clamp studies were performed at both euglycaemia (4.5 mmol/l glucose) and hypoglycaemia (2.5 mmol/l glucose).RESULTSIn normal subjects, plasma C‐peptide levels were suppressed by 66% during the euglycaemic hyperinsulinaemic clamps (P < 0.01). In contrast, in insulinoma patients, plasma C‐peptide levels increased by 25% during the clamps (P < 0.05). In the hypoglycaemic hyperinsulinaemic clamps, plasma C‐peptide levels were nearly completely (91%) suppressed in normal subjects and partially (39%) suppressed in patients with insulinoma (P < 0.01). The decrease in C‐peptide levels during the hypoglycaemic clamps was > 30% in 12 (75%) of 16 insulinoma patients and > 50% in 8 (50%) patients.CONCLUSIONSThis study demonstrated that in patients with insulinoma, insulin secretion was not suppressed by exogenous insulin during euglycaemia but was suppressed during hypoglycaemia, although the degree of suppression was less than that in normal subjects. Our results suggest that the feedback regulation of insulin secretion by exogenous insulin is partially retained in patients with insulinoma.
Restoration of species‐rich grassland on arable land: assessing the limiting processes using a multi‐site experiment
Authors: Pywell Richard F. , Bullock James M. , Hopkins Alan , Walker Kevin J. , Sparks Tim H. , Burke Mike J.W. , Peel Steve 
Published: July 2002

Summary

Agricultural intensification has resulted in the reduction and fragmentation of species‐rich grasslands across much of western Europe.
We examined the key ecological processes that limit the creation of diverse grassland communities on ex‐arable land in a multi‐site experiment over a wide variety of soil types and locations throughout lowland Britain.
The results showed it was possible to create and maintain these communities successfully under a hay‐cutting and grazing management regime. Furthermore, there was a high degree of repeatability of the treatment effects across the sites.
Lack of seed of desirable species was the key factor limiting the assembly of diverse grassland communities. Sowing a species‐rich seed mixture of ecologically adapted grassland plants was an effective means of overcoming this limitation. Community assembly by natural colonization from the seed bank and seed rain was a slow and unreliable process. However, there was no evidence to suggest that sowing a species‐poor grass‐dominated seed mixture made the vegetation any less susceptible to colonization by desirable species than allowing natural regeneration to take place.
Deep cultivation caused significant reductions in soil P and K concentrations across the sites. This had a significant beneficial effect on the establishment and persistence of sown forbs in all years. It also resulted in a significant reduction in the number of unsown weedy grasses. However, for both variables these differences were very small after 4 years.
Sowing a nurse crop significantly reduced the number of unsown grass species, but had no beneficial effect on the establishment of desirable species.
Treatments sown with the species‐rich seed mixture following deep cultivation corresponded most closely to the specified target communities defined by the UK National Vegetation Classification. Natural regeneration and treatments sown with the species‐poor seed mixture were much less similar to the target. The sites on circum‐neutral soils achieved the greatest degree of similarity to the target. Those on calcareous and acid soils failed to achieve their targets and most closely resembled the target for neutral soils. This reflected the poor performance of the sown preferential species for these communities.
Growth Hormone‐Releasing Hormone Decreases Voltage‐Gated Potassium Currents in GH4C1 Cells
Authors: Xu R. , Clarke I. J. , Chen S. , Chen C. 
Published: July 2002

AbstractThe electrophysiological properties of anterior pituitary somatotropes integrally involve the function of voltage‐gated K+ currents. In this study, we have used GH4C1 cell lines to investigate the effect of human GHRH on voltage‐gated K+ currents. Because of a clear ‘rundown’ of the K+ current with classic whole cell recording (WCR) without ATP in pipette solution, nystatin‐perforated WCR was the major recording configuration used. Using a low Ca2+ (0.5 mM) bath solution containing Co2+ (1 mM) and TTX (1 μM), GH4 cells predominantly exhibited an outward delayed rectifier K+ current (IK). Local application of growth hormone releasing hormone (GHRH) (100 nM) reversibly reduced the amplitude of the K+ currents (to 83% of control). There was no effect of GHRH on the activation curve of the K+ current and no difference observed using 2.5 mM Ca2+ or low Ca2+ (0.5 mM Ca2++1 mM Co2+) bath solutions. Under the condition of low Ca2+ bath solution, the application of apamin (1 μM) or charybdotoxin (1 μM), two specific blockers of the Ca2+‐activated K+ current, did not alter the K+ current or the response to GHRH. This reduction in the K+ current by GHRH was also observed with classic WCR with a pipette solution containing ATP (2 mM). The GHRH‐induced reduction in the K+ current was completely abolished by the presence of GDP‐β‐s (500 μM) in the pipette solution or by addition of PKC inhibitors, calphostin C (100 nM) and chelerythrine (1 μM), in bath solution. Inhibitor for cAMP‐PKA system (Rp‐cAMP and H89) did not affect the K+ current response to GHRH. These results suggest that GHRH reduces the voltage‐gated K+ current in GH4C1 cells, a response that is mediated by G‐proteins and PKC system but not by cAMP‐PKA system. The reduction in the K+ current may partially contribute to the GHRH‐stimulated growth hormone (GH) secretion.
Bacterial invasion of corneal epithelial cells
Authors: MRepSc V Vallas , McOptom F Stapleton , PhD M D P Willcox 
Published: July 2002

Purpose: The normal ocular surface is frequently colonized by commensal Gram‐positive species. Gram‐negative bacteria are often implicated in corneal infection and inflammation, particularly in association with soft contact lens wear. The aim of this study was to elucidate possible mechanisms of virulence in ocular bacteria. Methods: The susceptibility of a human corneal epithelial cell line to bacterial invasion and association was evaluated using the gentamicin exclusion assay. Organisms tested included isolates from corneal ulcers, corneal inflammation and ocular sites in asymptomatic individuals. Results: The commensal, non‐pathogenic bacterium Staphylococcus epidermidis and some pathogenic strains of Serratia marcescens did not invade corneal epithelial cells. In contrast, pathogenic strains of Pseudomonas aeruginosa associated with and invaded corneal epithelial cells. Conclusions: The increased association of P. aeruginosa, compared to other bacterial types, might be a reason for the more frequent association of this bacterium with contact‐lens‐associated microbial keratitis.