bluuebunny/crossref_metadata_2025 huggingface dataset:
Rate dependence of mechanically induced electrophysiological changes in right ventricle of anaesthetized lambs during pulmonary artery occlusion
Authors: Chen R. , Penny D. J. , Greve G. , Lab M. J.
Published: January 2004

Aim:  Mechanically induced early afterdepolarization (EAD) is morphologically similar but different in the mechanisms with drug‐induced EAD, which lead to arrhythmia. Pacing suppresses the drug‐induced EAD and arrhythmia, however the effect of pacing on mechanically induced EAD and arrhythmia is not clear. This study addressed this issue in right ventricle (RV) of anaesthetized lambs.

Methods:  Six lambs were anaesthetized, and their hearts exposed. Nine monophasic action potential (MAP) electrodes were placed on RV apex, outflow and inflow regions, and recorded before, during, and after a 10 s occlusion of pulmonary artery at a number of pacing rates.

Results:  Pacing significantly reduced the baseline MAP duration at 90% repolarization (MAPD90), decreased the reduction of MAPD at early repolarization at the peak of occlusion. Nonetheless, the percentage of reduction was not significantly different among them. Pacing was able to reduce the frequencies, size of mechanically induced EADs. MAPD90 at the peak of occlusion was all shortened during pacing rather than some lengthened at intrinsic rate. Therefore, the dispersion of MAPD90 at the peak of occlusion reduced from 86 ± 6 ms at intrinsic rate to 42 ± 4 ms at 120 beats min−1 , 38 ± 3 ms at 150 beats min−1 and 26 ± 3 ms at 170 beats min−1. Ultimately, pacing reduced/suppressed mechanically induced premature ventricular beats. These alterations were inversely related to heart rates.

Conclusion:  Pacing reduces/suppresses both stretch‐induced EADs and arrhythmia. These modulations are remarkably similar to those on other EADs by the pacing.
Myocardial ferritin content is closely related to the degree of ischaemia
Authors: Loncar R. , Flesche C. W. , Deussen A.
Published: January 2004

Aim:  Ferritin acts as an iron scavanger and thereby may reduce iron catalysed oxygen radical production during reperfusion injury. We tested the hypothesis that the myocardial ferritin concentration is enhanced during ischaemia in proportion to the blood flow reduction.

Methods:  In 10 anaesthetized, open chest Beagle dogs (six controls and four with 60 min coronary occlusion) regional myocardial blood flow (RMBF) was measured with the tracer microsphere technique and ferritin was determined in samples with an average mass of 125 mg (124–256 samples per heart).

Results:  Under physiological conditions heart rate was 88 ± 12 bpm, mean aortic pressure 98 ± 8 mmHg, and RMBF 0.99 ± 0.33 mL min−1 g−1. Data did not differ between experimental groups, P > 0.05. In the control group regional myocardial ferritin concentration averaged 11.76 ± 3.54 ng mg−1 protein and exhibited a significant blood flow independent heterogeneity (CVbiol = 0.27). However, between low and high flow areas (relative flow <0.5 and >1.5 times the average RMBF, respectively) no significant difference in ferritin was found, P > 0.05. In four experiments, in which regional blood flow was reduced by 40% to 0.60 ± 0.23 mL min−1 g−1, regional ferritin content was significantly higher as compared with the control group 27.95 ± 6.16 vs. 11.76 ± 3.54 ng mg−1 protein, respectively. An inverse relationship was observed between ferritin and RMBF, r = −0.61, P < 0.001. Thus, a reduction of RMBF of >80% was associated with a 2.75‐fold increase of the average ferritin content. Between subepicardium and subendocardium no significant difference in ferritin content was observed, neither in the control group nor in the group with induced ischaemia. Regions with control low and high flow responded similarly to the coronary constriction with regard to the local ferritin concentration: 27.88 ± 15.22 vs. 30.10 ± 14.91 ng mg−1, P > 0.05, respectively. A data analysis using Baye's theorem indicated that sensitivities were 0.28 and 0.94 for average flow reductions of 5 and 93%. In additional in vitro measurements (ischaemic incubation at 37 °C) myocardial ferritin content increased almost linearly within the first 60 min of incubation and thereafter remained unchanged.

Conclusions:  (1) Local physiological ferritin content in myocardium is heterogeneous and unrelated to control myocardial blood flow. (2) Ischaemia results in an enhanced ferritin content in relation to the degree of ischaemia. (3) The increase of myocardial ferritin requires a severe degree of ischaemia.
Muscle blood flow in response to concentric muscular activity vs. passive venous compression
Authors: Zhang Q. , Andersson G. , Lindberg L. G. , Styf J.
Published: January 2004

Aim:  To measure muscle blood flow (MBF) using photoplethysmography (PPG) following concentric muscular activity of the leg (active treatment) or passive venous compression (passive treatment) with or without venous obstruction.

Methods:  In study A, blood flow in the anterior tibial muscle was measured in 15 healthy subjects with a mean age of 30 years. In study B, blood flow in the gastrocnemius muscle was measured in nine healthy subjects with a mean age of 34 years. Subjects performed concentric muscular activity in one leg. Passive venous compression by a venous foot pump was applied in the contralateral leg.

Results:  MBF increased significantly following concentric muscular activity, but not following passive venous compression. MBF decreased in both legs when venous obstruction, induced by a thigh tourniquet, was applied. However, MBF was significantly higher following concentric muscular activity than passive venous compression.

Conclusion:  We conclude that concentric muscular activity produces higher MBF values than passive venous compression.
Different time course of changes in sarcoplasmic reticulum and myosin isoforms in rat soleus muscle at early stage of hyperthyroidism
Authors: Yamada T. , Inashima S. , Matsunaga S. , Nara I. , Kajihara H. , Wada M.
Published: January 2004

Aims and methods: 
We studied changes in the expression of myosin and sarcoplasmic reticulum (SR) Ca2+‐ATPase (SERCA) and in Ca2+ uptake and release rates by the SR in rat slow‐twitch soleus muscles treated with thyroid hormone (3,5,3′‐triiodo‐l‐thyronine, T3) for 1, 3, 7 and 21 days.

Results:  The content of fast SR Ca2+‐ATPase isoform SERCA1a protein significantly increased as early as 3 days of T3 treatment, while a rise in fast myosin heavy chain isoforms was found only 21 days after the onset of T3 administration. T3‐induced slow‐to‐fast transitions were much less pronounced in myosin light chain than in myosin heavy chain. Moreover, in vitro measurements of SR Ca2+‐handling capacity with indo‐1 indicated that increases in uptake rate preceded those of release rate (7 vs. 21 days).

Conclusion:  These data suggest that changes in the myosin and SERCA expressions seem not to occur in a coordinated manner at the early stage of hyperthyroidism and that intervention with T3 may temporarily produce slow‐twitch type I fibres which contain, in addition to slow SERCA2a isoform, the appreciable amounts of fast SERCA1a isoform. Moreover, it is speculated that some fibres in the hyperthyroid soleus muscles may temporarily acquire unique contractile properties distinct from normal fast and slow fibres.
Quantification of α‐subunit isoforms of Na,K‐ATPase in rat resistance vessels
Authors: Hansen O.
Published: January 2004

Aim:  Rat mesenteric resistance vessels (RV) were characterized with respect to concentration of individual α‐subunit isoforms of Na,K‐ATPase.

Methods:  Total vessel homogenates were used to avoid any loss or subfractionation of membranes. They were applied to sodium dodecyl sulphate gels and, for calibration, in parallel lanes were run purified rat Na,K‐ATPase preparations with known isoform distribution and content. The capacity per mg protein for Na+‐dependent 32P‐phosphorylation of Na,K‐ATPase isolated from rat kidney was used for α1 calibration and that for high‐affinity (3H)ouabain binding of Na,K‐ATPase isolated from rat brain was used for (α2 + α3) calibration. Western blots containing homogenate proteins and reference enzyme were incubated with isoform‐specific antibodies and radiolabelled secondary antibodies. The signals from adjacent α spots were used for qualitative and quantitative characterization of rat vessels.

Results:  A concentration of 100.7 ± 14.4 pmol (n = 11) per g wet weight of the α1‐isoform containing Na,K‐ATPase was found in RV from 12–14‐week rats. A much lower and more unreliable content of α2‐ and α3‐isoforms was found. These ouabain‐sensitive isoforms seem to represent a maximum of 5–10% each compared with the ouabain‐insensitive rat α1‐isoform.

Conclusions:  The isoform pattern in RV, in which the isoform with high/intermediate Na+‐affinity is the absolutely dominating one representing nearly all sodium pumps in this tissue, is very different from that seen in rat skeletal muscles. Due to the high content of the ouabain‐insensitive α1‐isoform in rat RV this species would seem a less relevant model in studies addressing a role of cardiac glycosides and putative endogenous ouabain‐like factors in hypertension.
Muscle hypertrophy following 5‐week resistance training using a non‐gravity‐dependent exercise system
Authors: Tesch P. A. , Ekberg A. , Lindquist D. M. , Trieschmann J. T.
Published: January 2004

Aim:  The efficacy of a mechanical, gravity‐independent resistance exercise (RE) system to induce strength gains and muscle hypertrophy was validated. Designed for space crew in orbit, this technique offers resistance during coupled concentric and eccentric actions by utilizing the inertia of a rotating flywheel(s), set in motion by the trainee.

Methods:  Ten middle‐aged (30–53 years) men and women performed four sets of seven maximal, unilateral (left limb) knee extensions two or three times weekly for 5 weeks. Knee extensor force and electromyographic (EMG) activity of the three superficial quadriceps muscles were measured before and after this intervention. In addition, with the use of magnetic resonance imaging (MRI), volume of individual knee extensor and ankle plantar flexor muscles was assessed.

Results:  Over the 12 training sessions, the average concentric (CON) and eccentric (ECC) force generated during exercise increased by 11% (P < 0.05). Likewise, maximal isometric strength (maximal voluntary contraction, MVC) at 90 and 120° knee angle increased by (P < 0.05) 11 and 12% respectively, after training. Neither individual quadriceps muscle showed a change (P > 0.05) in maximal integrated EMG (iEMG) activity. Quadriceps muscle volume increased by 6.1% (P < 0.05). Although the magnitude of response varied, all individual quadriceps muscles showed increased (P < 0.05) volume after training. As expected, ankle plantar flexor volume of the trained limb was unchanged (P > 0.05). Likewise, MVC, CON and ECC force, iEMG and knee extensor and plantar flexor muscle volume were unaltered (P > 0.05) in the right, non‐trained limb.

Conclusion:  The results of this study show that the present RE regimen produces marked muscle hypertrophy and important increases in maximal voluntary strength and appears equally effective as RE paradigms using gravity‐dependent weights, in this regard.
Treatment with campath‐1H for relapsed chronic lymphocytic leukemia after allogeneic peripheral blood stem cell transplantation does not abrogate the development of chronic GVHD
Authors: Wolff Daniel , Steiner B. , Stilgenbauer S. , Kahl C. , Leithäuser M. , Junghanss C. , Wilhelm S. , Kleine H. D. , Zimmermann R. , Hartung G. , Casper J. , Freund M.
Published: January 2004

The graft vs. leukemia (GVL) effect is one of the most important factors of anti‐tumor activity after allogeneic hematopoetic stem cell transplants (alloSCT). Its effectiveness depends mainly on the tumor biology as well as the tumor burden. Patients with a high tumor burden may not respond to GVL‐effect despite otherwise sensitive biology. Campath‐1H is known as an effective treatment of chronic lymphocytic leukemia (CLL). Due to its ability to induce profound immunosuppression, it has also been used as part of conditioning regimens before alloSCT. We report a patient, who received campath‐1H in combination with docetaxel for treatment of chemotherapy and donor lymphocyte infusion resistant CLL after alloSCT, who developed shortly after discontinuation of treatment with campath‐1H severe eosinophilia of the peripheral blood and typical clinical as well as histological signs of cutaneous chronic graft vs. host disease followed by complete clearance of CLL. The clinical course demonstrates the impact of the tumor burden on the GVL‐effect, as well as the effectiveness of campath‐1H in the presence chemo‐resistance in a patient with CLL. Furthermore, the GVL effect was not abrogated by the use of campath‐1H.
Multiplex analysis of the most common mutations related to hereditary haemochromatosis: two methods combining specific amplification with capillary electrophoresis
Authors: Gómez‐Llorente Carolina , Antúnez Adelaida , Blanco Sonia , Suarez Antonio , Gómez‐Capilla Jose Antonio , Farez‐Vidal M. Esther
Published: January 2004

We present the first application of a multiplex multicolour assay for the simultaneous detection of three of the most frequent mutations related to hereditary haemochromatosis (C282Y, H63D and S65C), using fluorescent detection and capillary electrophoresis. We describe two methods: the first is based on a single base extension assay, resulting in a single base difference of the extended products; and the second is a competitive allele‐specific polymerase chain reaction (PCR), based on competition between allele‐specific primers. Specificity of the latter primers is enhanced with a mismatch at the antepenultimate nucleotide. Primers are designed to amplify products of different sizes and with different fluorescent dyes in order to accurately distinguish all possible combinations of genotypes (homozygous and heterozygous for each mutation) in a multiplex PCR analysis. An advantage of the present approach is that capillary electrophoresis analysis of the amplified products enables easy, rapid, unambiguous and high resolution discrimination between wild‐type and mutant alleles, although different mutations may be present in the multiplex analysis. This will facilitate automated genotyping for routine molecular diagnostics and large‐scale genetic studies.
Association of pyoderma gangrenosum and sterile osteomyelitis in a patient having myelodysplastic syndrome with der(1;7)(q10;q10)
Authors: Yoshida Chikashi , Kojima Hiroshi , Ishigaki Taro , Katsura Yukitaka , Kaneko Shin , Suzukawa Kazumi , Hasegawa Yuichi , Kawachi Yasuhiro , Otsuka Fujio , Nagasawa Toshiro
Published: January 2004

Neutrophilic dermatoses such as Sweet's disease and pyoderma gangrenosum (PG) are occasionally associated with myelodysplastic syndrome (MDS). We present here a 67‐yr‐old male having PG and sterile osteomyelitis in association with underlying MDS (refractory anemia) and Crohn's disease. To establish the diagnosis of MDS, sternal bone marrow puncture was performed, which showed chromosomal abnormality containing der(1;7)(q10;q10). After the puncture, he suffered from gradually progressive skin ulceration, flare, and bone pain. Magnetic resonance imaging (MRI) of the sternum showed severe inflammation in the sternum and the overlying subcutaneous tissue. All of the cultures obtained from the wound were negative for both bacteria and fungus. Biopsy was performed from the antero‐sternal skin lesion, which showed epidermal ulceration with prominent infiltration of neutrophils. He was thus diagnosed as having PG and sterile osteomyelitis, and was treated with prednisolone, which completely resolved the symptoms. We consider that the bone marrow aspiration in the present patient provoked PG and sterile osteomyelitis. As was previously reported by others, certain chromosomal abnormalities in MDS may be related with the development of neutrophilic dermatoses.
Plasma level of the macrophage‐derived soluble CD163 is increased and positively correlates with severity in Gaucher's disease
Authors: Møller Holger Jon , Fost Maaike de , Aerts Hans , Hollak Carla , Moestrup Søren Kragh
Published: January 2004

Recently, soluble CD163 (sCD163) has been identified as a macrophage/monocyte‐specific plasma protein and increased concentrations have been measured in patients with infection and myeloid leukaemia. In the present study we investigated the levels of sCD163 in patients with Gaucher's disease, an inherited lysosomal storage disorder characterised by hepato‐ and spleno‐megaly due to excessive accumulation of macrophages. The sCD163 plasma levels, median (25–75 percentiles), were far above the levels in normal subjects [7.1 mg/L (4.8–10.3) vs. 1.9 mg/L (1.5–2.4), P < 0.0001]. After initiation of enzyme supplementation therapy, the sCD163 levels were significantly reduced [4.7 mg/L (3.2–6.6), P = 0.0004]. sCD163 correlated with disease severity (rho = 0.43, P < 0.0061) and chitotriosidase activity (rho = 0.71, P > 0.0001). This study further establishes that sCD163 may be a valuable laboratory parameter in monitoring disease with increased macrophage activity.
Monoclonal antibodies in the treatment of autoimmune cytopenias
Authors: Robak Tadeusz
Published: January 2004

In recent years, clinical studies have been undertaken with selected monoclonal antibodies (MoAbs) in the treatment of several hematological diseases, especially in malignant disorders. However, some clinical observations indicate that MoAbs may be an important alternative for the conventional therapy of some autoimmune disorders. Two MoAbs directed against CD20 antigen (rituximab, Rituxan, Mabthera) and CD52 antigen (alemtuzumab, Campath‐1H) seem to be especially useful for this purpose. Autoimmune cytopenias have been investigated in the last few years with positive preliminary results. Rituximab seems to be an effective and safe agent for the treatment of immune thrombocytopenias, autoimmune hemolytic anemia, cold agglutinin disease and pure red cell aplasia. Although the case series are small, rituximab seems to be an effective and safe agent for the treatment of these diseases. Clinical experience with alemtuzumab in patients with autoimmune cytopenias is even more limited than with rituximab. However, preliminary results indicate that further studies with this MoAb are warranted. A longer follow‐up and the studies on larger number of patients are needed to determine the real value of these new approaches in autoimmune cytopenias. Recent experiences with the use of MoAbs in treatment of these diseases are the subject of this review.
Viral clearance occurs very early during the natural resolution of hepatitis C virus infection in persons with haemophilia
Authors: Eyster M. E. , Sanders J. , Goedert J. J.
Published: January 2004

Summary.  We studied spontaneous hepatitis C virus (HCV) RNA clearance in 12 haemophilic patients. In their earliest anti‐HCV positive samples, HCV RNA was undetectable in eight patients (66%), positive by polymerase chain reaction (PCR) but negative by branched‐DNA (bDNA) in three others, and quantifiable by bDNA (4839 IU/mL) in only one patient. In contrast, in earliest anti‐HCV positive samples from eight matched controls who had persistent viremia, HCV RNA was quantifiable by bDNA in seven (P = 0.0008) and at higher levels (range 4644–678 515 IU/mL; median 43 532 IU/mL). From initial HCV infection, HCV RNA cleared in 7 months or less in four patients and in 1–2 years in six others. HCV persisted for 5 years before clearance in the absence of repeated exposure in one patient. We conclude that HCV clearance usually but not always occurs within 1–2 years after infection and is more likely in those with lower than in those with higher early viral loads.
An economic model of haemophilia in Mexico
Authors: Martínez‐Murillo C. , Quintana S. , Ambriz R. , Benitez H. , Berges A. , Collazo J. , Esparza A. , Pompa T. , Taboada C. , Zavala S. , Larochelle M. R. , Bentkover J. D. ,   the Comité Mexicano de Hemostasia y Trombosis (CMHT) Economic Model of Hemophilia in Mexico Research Team
Published: January 2004

Summary.  A model was developed to assess the lifetime costs and outcomes associated with haemophilia in Mexico. A retrospective chart review of 182 type A haemophiliacs was conducted for patients aged 0–34 years receiving one of three treatments: (i) cryoprecipitate at clinic; (ii) concentrate at home; or (iii) concentrate at clinic. Patients treated at home experienced 30% less joint damage, used 13–54% less factor VIII, had four times fewer clinic visits, and utilized half as many hospital days than those treated at a clinic. For cryoprecipitate at clinic patients, the annual incidence rates of HCV and HIV were calculated to be 3.6% and 1.4% respectively. The life expectancy for patients receiving cryoprecipitate and those receiving concentrate was estimated to be 49 years and 69 years respectively, with 58% of cryoprecipitate patients predicted to die of AIDS before age 69. Across the lifespan, the average annual cost of care was US$11 677 (MN$110 464) for cryoprecipitate at clinic patients, US$10 104 (M$95 580) for concentrate at home patients and US$18 819 (MN$178 027) for concentrate at clinic patients. Using a 5% discount rate, the incremental lifetime cost per year of life added for treatment with concentrate at home compared with cryoprecipitate at a clinic was US$738 (MN$6981). Rank order stability analysis demonstrated that the model was most sensitive to the cost of fVIII. These results indicate that treatment with concentrate at home compared with cryoprecipitate at a clinic substantially improves clinical outcomes at reduced annual cost levels.
Successful treatment of acquired factor VIII inhibitor with cyclosporin
Authors: Au W. Y. , Lam C. C. K. , Kwong Y. L.
Published: January 2004

Summary.  Acquired factor VIII inhibitor causes a rare but life‐threatening form of bleeding disorder, owing to the formation of auto‐antibodies against FVIII. Treatment modalities include the use of immunosuppressive drugs such as cyclophosphamide and corticosteroids, plasmapheresis and i.v. immunoglobulin. A patient with idiopathic acquired FVIII inhibitor presented with serious bleeding complications resistant to all the above therapeutic modalities. Treatment with cyclosporin, however, resulted in a prompt and complete response. The lack of side‐effects and the relatively quick response suggest that cyclosporin may be tried as front line treatment for patients with acquired FVIII inhibitors.
Modelling haemophilia epidemiology and treatment modalities to estimate the unconstrained factor VIII demand
Authors: Stonebraker J. S. , Amand R. E. , Bauman M. V. , Nagle A. J. , Larson P. J.
Published: January 2004

Summary.  The article presents a new method for estimating the unconstrained factor VIII (FVIII) demand based on the principles of decision analysis. Epidemiology and treatment modalities were integrated into a model for unconstrained FVIII demand. Assumptions for each variable with impact on the unconstrained FVIII demand were defined and probability estimates for these variables were obtained from the literature and medical experts. The sensitivity of the unconstrained FVIII demand to each of the variables was determined, and the variables with the greatest impact were modelled probabilistically. The probability‐weighted average for the unconstrained FVIII demand model was 6.9 units per capita with a 90% uncertainty interval of 2.7–13.6 units per capita. When compared with FVIII usage in countries, only Luxembourg's use of FVIII (7.7 units per capita) exceeded the probability‐weighted average for the modelled unconstrained FVIII demand. As better information becomes available, revision of model variables is easily accomplished allowing for a more accurate and dynamic forecast of demand over time. More accurate modelling of the ‘true’ demand longitudinally should help prevent shortages of FVIII concentrates such as those that have occurred in the past. In addition, a more accurate forecast of FVIII demand will allow national health care policy makers to better allocate financial and other resources. Sufficient and consistent supply of FVIII concentrates and appropriate financing of haemophilia care will allow the clinical benefits of more aggressive treatment regimens such as prophylaxis to be realized.
Development and validation of a measure of disease‐specific quality of life in young children with haemophilia
Authors: Manco‐Johnson M. , Morrissey‐Harding G. , Edelman‐Lewis B. , Oster G. , Larson P.
Published: January 2004

No disease‐specific tool for measuring health‐related quality of life (HRQL), an important outcome when assessing medical treatment, has been developed for children with haemophilia. The goal of this study was to develop a parent‐administered questionnaire for evaluating quality of life (QOL) in paediatric haemophilia patients between 2 and 6 years of age. After interviewing physicians (5), nurses (5) and parents (10) of children with haemophilia aged between 2 and 6 years, 92 questions were developed and pilot‐tested with parents (44) of children with haemophilia to create a 39‐question instrument that assessed somatic symptoms, physical functioning, sleep disturbance, stigma, social functioning, fear/resentment, mood/behaviour, restrictions, treatment upset, haemophilia concern and energy level. Reliability and validity were evaluated with 103 parents of children with haemophilia and parents of 249 age‐ and gender‐matched healthy children. Estimates of scale reliability (internal consistency) for eight multi‐item scales ranged from 0.73 to 0.94. Results showed construct validity (correlations with age, severity of haemophilia, treatment type, days absent and days confined to bed) and correlated with two general, paediatric quality‐of‐life instruments (Impact on Family Scale and Functional Status II(R). Discriminant validity was demonstrated by comparing scores between patients receiving/not receiving prophylactic therapy and between haemophilia patients and healthy controls. This disease‐specific HRQL measure should be of use in clinical trials and general practice to better understand disease and treatment impacts in young children with haemophilia.
Combination therapy with ribavirin and interferon in a cohort of children with hepatitis C and haemophilia followed at a pediatric haemophilia treatment center
Authors: Puetz J. , Thrower M. , Kane R. , Bouhasin J.
Published: January 2004

Summary.  Nearly all children with bleeding disorders who received factor concentrates prior to the late 1980s were infected with hepatitis C. Treatment of adults infected with hepatitis C with combination therapy consisting of ribavirin and interferon has shown sustained response rates of 30–60%. Little data is available on the response of children infected with hepatitis C treated with combination therapy, especially those with bleeding disorders. We wish to report a single paediatric haemophilia treatment center's results of treatment of adolescents with haemophilia and hepatitis C infection with combination therapy. All patients followed at the haemophilia treatment center with hepatitis C, who were human immunodeficiency virus (HIV) negative and had a measurable hepatitis C viral load were eligible. Study patients received at least 6 months of 3 MU interferon‐α via subcutaneous injection three times per week and 1000 mg day−1 of ribavirin. Eleven patients agreed to participate in the study. Three patients had an un measurable viral load after 6 months of combination therapy. All three completed 12 months of medication and continued to remain free of hepatitis C for 12 months after discontinuation of therapy. Side‐effects of combination therapy were significant but tolerable. The sustained response rate in this study is similar to the historical response rate seen in adults but less than the other reported response rates seen in children treated with combination therapy. Given the toxicity of combination therapy, and natural history of hepatitis C infection in children, consideration of a liver biopsy to evaluate disease progression prior to considering antiviral medications is warranted.
Design of a pH‐sensitive pore‐forming peptide with improved performance
Authors: Haas D.H. , Murphy R.M.
Published: January 2004

Abstract: 
GALA is a 30 residue synthetic peptide designed to interact with membranes in a pH‐sensitive manner, with potential applications for intracellular drug and gene delivery. Upon reduction of the pH from neutral to acidic, GALA switches from random coil to α‐helix, inserts into lipid bilayers, and forms oligomeric pores of defined size. Its simple sequence and well‐characterized behavior make the peptide an excellent starting point to explore the effects of sequence on structure, pH sensitivity, and membrane affinity. We describe synthesis and characterization of two derivatives of GALA, termed GALAdel3E and YALA. GALAdel3E has a deletion of three centrally located glutamate residues from GALA, while YALA replaces one glutamate residue with the unusual amino acid 3,5‐diiodotyrosine. Both derived peptides retain pH sensitivity, showing no ability to cause leakage of an encapsulated dye from unilamellar vesicles at pH 7.4 but substantial activity at pH 5. Unlike GALA, neither peptide undergoes a conformational change upon reduction of the pH, remaining α‐helical throughout. Interestingly, the pH at which the peptides activate is shifted, with GALA becoming active at pH ∼5.7, GALAdel3E at pH ∼6.2, and YALA at pH ∼6.7. Furthermore, the peptides GALAdel3E and YALA show improved activity compared with GALA for cholesterol‐containing membranes, with YALA retaining the greatest activity. Improved activity in the presence of cholesterol and onset of activity in the critical range between pH 6 and 7 may make these peptides useful in applications requiring intracellular delivery of macromolecules, such as gene delivery or anti‐cancer treatments.
The effect of a side chain‐backbone swap on protein stability
Authors: Flinders K.T. , Flynn P.F. , Yu Y.B.
Published: January 2004

Abstract:  To assess the relative importance of backbone hydrogen bonding (H‐bonding) vs. side chain hydrophobicity in protein structural formation, a method called side chain‐backbone swap is proposed. Such a method swaps the side chain and backbone portions of certain amino acid residues, such as Asp, Glu, Asn, Gln, Lys, and Arg. Such a swap retains the sequence of a polypeptide and preserves the identity of the backbone linkage. On the other hand, the swap disrupts backbone H‐bonding geometry because of the introduction of extra methylene groups into the peptide backbone. In this project, we chose the two‐stranded α‐helical coiled‐coil to implement side chain‐backbone swap. A pair of 36‐residue peptides was designed. The two peptides have identical sequence with four residues in each heptad repeat occupied by glutamyl residues. Each glutamic acid was incorporated either as α‐glutamyl residue (the peptide is denoted as α‐Glu‐36) or as γ‐glutamyl residue (the peptide is denoted as γ‐Glu‐36). The inter‐conversion between the two peptides constitutes a side chain‐backbone swap. Residues constituting the hydrophobic core of the coiled‐coil, however, are left unchanged. The peptide pair was characterized by circular dichroism spectroscopy, reversed‐phase liquid chromatography (RPLC), and two‐dimensional nuclear magnetic resonance (NMR). The results indicate that α‐Glu‐36 is a two‐stranded α‐helical coiled‐coil while γ‐Glu‐36 lacks stable structural elements. It is concluded that, at least for coiled‐coils where hydrophobic interactions are predominantly long‐range, local backbone H‐bonding is a required for structural formation, consistent with a hierarchic folding mechanism. The methodological implication of side chain‐backbone swap is also discussed.
Support vector machines for prediction of peptidyl prolyl cis/trans isomerization
Authors: Wang M.‐L. , Li W.‐J. , Xu W.‐B.
Published: January 2004

Abstract:  A new method for peptidyl prolyl cis/trans isomerization prediction based on the theory of support vector machines (SVM) was introduced. The SVM represents a new approach to supervised pattern classification and has been successfully applied to a wide range of pattern recognition problems. In this study, six training datasets consisting of different length local sequence respectively were used. The polynomial kernel functions with different parameter d were chosen. The test for the independent testing dataset and the jackknife test were both carried out. When the local sequence length was 20‐residue and the parameter d = 8, the SVM method archived the best performance with the correct rate for the cis and trans forms reaching 70.4 and 69.7% for the independent testing dataset, 76.7 and 76.6% for the jackknife test, respectively. Matthew's correlation coefficients for the jackknife test could reach about 0.5. The results obtained through this study indicated that the SVM method would become a powerful tool for predicting peptidyl prolyl cis/trans isomerization.
Differential selection of growth rate-related traits in wild barley, Hordeum spontaneum, in contrasting greenhouse nutrient environments
Authors: Verhoeven K. J. F. , Biere A. , Nevo E. , Van Damme J. M. M.
Published: January 2004

Across-species comparisons show that inherent variation in relative growth rate (RGR) and its underlying traits are correlated with habitat productivity. In this study, we test the hypothesis that growth rate-related traits confer differential selective effects in contrasting nutrient environments. We specifically test whether high RGR is targeted by selection in nutrient-rich environments whereas low values of traits that underlie RGR [specific leaf area (SLA), leaf mass fraction and leaf area ratio (LAR)] confer a direct fitness advantage in nutrient-poor environments, resulting in selection of low RGR as a correlated response. We measured RGR, its underlying component traits, and estimated fitness in a range of wild barley (Hordeum spontaneum) accessions grown under high and low nutrient conditions. Selection on component traits differed between the two environments, while total selection of RGR was not significant. Using multiple regression and path analysis to estimate direct fitness effects, a selective advantage of high LAR and SLA was demonstrated only under nutrient-rich conditions. While supporting the view that observed associations between habitat richness and some RGR-component traits reflect adaptation to differing nutrient regimes, our data suggest that direct selection targets component traits rather than RGR itself.
Kin discrimination and sex ratios in a parasitoid wasp
Authors: Reece S. E. , Shuker D. M. , Pen I. , Duncan A. B. , Choudhary A. , Batchelor C. M. , West S. A.
Published: January 2004

Sex ratio theory provides a clear and simple way to test if nonsocial haplodiploid wasps can discriminate between kin and nonkin. Specifically, if females can discriminate siblings from nonrelatives, then they are expected to produce a higher proportion of daughters if they mate with a sibling. This prediction arises because in haplodiploids, inbreeding (sib-mating) causes a mother to be relatively more related to her daughters than her sons. Here we formally model this prediction for when multiple females lay eggs in a patch, and test it with the parasitoid wasp Nasonia vitripennis. Our results show that females do not adjust their sex ratio behaviour dependent upon whether they mate with a sibling or nonrelative, in response to either direct genetic or a range of indirect environmental cues. This suggests that females of N. vitripennis cannot discriminate between kin and nonkin. The implications of our results for the understanding of sex ratio and social evolution are discussed.
Flowering time plasticity in Arabidopsis thaliana: a reanalysis of
Authors: Stinchcombe J. R. , Dorn L. A. , Schmitt J.
Published: January 2004

Environmental variation in temperature can have dramatic effects on plant morphology, phenology, and fitness, and for this reason it is important to understand the evolutionary dynamics of phenotypic plasticity in response to temperature. We investigated constraints on the evolution of phenotypic plasticity in response to a temperature gradient in the model plant Arabidopsis thaliana by applying modern analytical tools to the classic data of Westerman & Lawrence (1970). We found significant evidence for two types of constraints. First, we detected numerous significant genetic correlations between plastic responses to temperature and the mean value of a trait across all environments, which differed qualitatively in pattern between the set of ecotypes and the set of mutant lines in the original sample. Secondly, we detected significant costs of flowering time plasticity in two of the three experimental environments, and a net pattern of selection against flowering time plasticity in the experiment overall. Thus, when explored with contemporary methods, the prescient work of Westerman & Lawrence (1970) provides new insights about evolutionary constraints on the evolution of plasticity.
Reproductive character displacement is not the only possible outcome of reinforcement
Authors: Lemmon A. R. , Smadja C. , Kirkpatrick M.
Published: January 2004

We study the form of the clines in a female mating preference and male display trait using simulations of a hybrid zone. Allopatric populations of two species are connected by demes in a stepping stone arrangement. Results show that reproductive character displacement (a pattern of increased prezygotic isolation in sympatry compared with allopatry) may or may not result when there is reinforcement (defined here as the strengthening of prezygotic isolation as a result of selection against hybrids, relative to the amount of prezygotic isolation present when hybrids are not selected against). Further, reproductive character displacement of the preference may or may not occur when it occurs in the male display. We conclude that the absence of reproductive character displacement is not evidence against the operation of reinforcement.
Effectiveness of sexual selection in preventing fitness deterioration in bulb mite populations under relaxed natural selection
Authors: Radwan J. , Unrug J. , Śnigórska K. , Gawrońska K.
Published: January 2004

Under the ‘good genes’ mechanism of sexual selection (SS), females benefit from mate choice indirectly: their offspring inherit genes of the preferred, high quality fathers. Recent models assume that the genetic variance for male quality is maintained by deleterious mutations. Consequently, SS can be predicted to remove deleterious mutations from populations. We tested this prediction by relaxing selection in populations of the bulb mite, thus increasing their rate of accumulation of deleterious mutation. SS, allowed to operate in half of these populations, did not prevent the fitness decline observed in the other half of the relaxed selection lines. After 11 generations of relaxed selection, female fecundity in lines in which males were allowed to compete for females declined compared with control populations by similar amount as in monogamous lines (17.5 and 14.5%, respectively), whereas other fitness components (viability, longevity, male reproductive success) did not differ significantly between both types of lines and control populations.
Strong premating divergence in a unimodal hybrid zone between two subspecies of the house mouse
Authors: Smadja C. , Catalan J. , Ganem G.
Published: January 2004

Although selection against hybridization is expected to generate prezygotic divergence in unimodal hybrid zones, such a pattern has been seldom described. This study aims to better understand how prezygotic mechanisms may evolve in such zones. We investigated prezygotic divergence between populations of two subspecies of mice (Mus musculus musculus and M. m. domesticus) located at the edges of their unimodal hybrid zone in Denmark, and we developed an original multiple-population choice-test design, which allows assessment of within and between subspecies variation. Our study demonstrates that a strong assortative preference characterises one of the two subspecies (musculus) and that urinary signals are involved in this subspecies recognition. Taking into account the specific genetic and geographical characteristics of the Danish hybrid zone, we discuss the influence of the above pattern on its fate and the mechanisms that could have favoured this prezygotic divergence, among which the role of recombined populations constituting the core of the zone.
Floral evolution and pollinator mate choice in a sexually deceptive orchid
Authors: Schiestl F. P.
Published: January 2004

Sexually deceptive orchids mimic sex pheromones and appearance of female insects to attract males, which pollinate the flowers in an attempted mating. This study examines the effects of pollinator mate choice on orchid floral evolution using the Thynnine wasp Neozeleboria cryptoides (Smith) (Hymenoptera: Tiphiidae), which pollinates the sexually deceptive orchid Chiloglottis trapeziformis Fitzg. (i) When male wasps were given the choice between two female dummies of different sizes and identical amount of synthetic pheromone, they preferentially attempted to copulate with medium-sized dummies over small dummies. (ii) When given the choice between two dummies of identical size but different amounts of pheromone, males preferred the larger amount of pheromone. Larger amounts of pheromone generally attracted more males than smaller amounts. (iii) Orchid flower labella, which mimic a female body, were significantly longer and broader than female wasp bodies, and the flowers also produced on average 10 times more ‘pheromone’ than females. The evolution and maintenance of these exaggerated mating signals is likely to be mediated by the male pollinator behaviour demonstrated here. (iv) When five dummies were offered simultaneously in a 10 cm circular array, males rarely attempted copulation on more than one dummy during a single visit. This behaviour may foster the evolution or maintenance of clonality in C. trapeziformis, as it will minimize pollen exchange within clones.
Complex evolution of orthologous and paralogous decarboxylase genes
Authors: Sáenz-de-Miera L. E. , Ayala F. J.
Published: January 2004

The decarboxylases are involved in neurotransmitter synthesis in animals, and in pathways of secondary metabolism in plants. Different decarboxylase proteins are characterized for their different substrate specificities, but are encoded by homologous genes. We study, within a maximum-likelihood framework, the evolutionary relationships among dopa decarboxylase (Ddc), histidine decarboxylase (Hdc) and α-methyldopa hypersensitive (amd) in animals, and tryptophan decarboxylase (Wdc) and tyrosine decarboxylase (Ydc) in plants. The evolutionary rates are heterogeneous. There are differences between paralogous genes in the same lineages: 4.13 × 10−10 nucleotide substitutions per site per year in mammalian Ddc vs. 1.95 in Hdc; between orthologous genes in different lineages, 7.62 in dipteran Ddc vs. 4.13 in mammalian Ddc; and very large temporal variations in some lineages, from 3.7 up to 54.9 in the Drosophila Ddc lineage. Our results are inconsistent with the molecular clock hypothesis.
Effects of host condition on susceptibility to infection, parasite developmental rate, and parasite transmission in a snail–trematode interaction
Authors: Krist A. C. , Jokela J. , Wiehn J. , Lively C. M.
Published: January 2004

Whether or not organisms become infected by parasites is likely to be a complex interplay between host and parasite genotypes, as well as the physiological condition of both species. Details of this interplay are very important because physiology-driven susceptibility has the potential to confound genetic coevolutionary responses. Here we concentrate on how physiological aspects of infection may interfere with genetic-based infectivity in a snail–trematode (Potamopyrgus antipodarum/Microphallus sp.) interaction by asking: (1) how does host condition affect susceptibility to infection? and (2) how does host condition affect the survival of infected individuals? We manipulated host condition by experimentally varying resources. Contrary to our expectation, host condition did not affect susceptibility to infection, suggesting that genetics are more important than physiology in this regard. However, hosts in poor condition had higher parasite-induced mortality than hosts in good condition. Taken together, these results suggest that coevolutionary interactions with parasites may depend on host condition, not by altering susceptibility, but rather by affecting the likelihood of parasite transmission.
Consequences of inter-population crosses on developmental stability and canalization of floral traits inDalechampia scandens(Euphorbiaceae)
Authors: Pélabon C. , Carlson M. L. , Hansen T. F. , Yoccoz N. G. , Armbruster W. S.
Published: January 2004

Congruence between changes in phenotypic variance and developmental noise in inter-population hybrids was analysed to test whether environmental canalization and developmental stability were controlled by common genetic mechanisms. Developmental stability assessed by the level of fluctuating asymmetry (FA), and canalization by the within- and among-individual variance, were measured on several floral traits of Dalechampia scandens (Euphorbiaceae). Hybridization affected canalization. Both within- and among-individual phenotypic variance decreased in hybrids from populations of intermediate genetic distance, and strongly increased in hybrids from genetically distant populations. Mean-trait FA differed among cross-types, but hybrids were not consistently more or less asymmetric than parental lines across traits. We found no congruence between changes in FA and changes in phenotypic variance. These results suggest that developmental stability (measured by FA) and canalization are independently controlled. This study also confirms the weak relationship between FA and the breakdown of coadapted gene complexes following inter-population hybridization.
Ecological and morphological patterns in communities of land snails of the genusMandarinafrom the Bonin Islands
Authors: Chiba Satoshi
Published: January 2004

The land snail genus Mandarina has undergone extensive radiation within the Bonin Islands in the west Pacific. The preferred above-ground vegetation heights of sympatric species were clearly different. They separated into arboreal, semi-arboreal, exposed ground and sheltered ground ecotypes. Shells of species with different ecotypes differ markedly, but shells of species with the same ecotype are very similar to each other. Shell morphologies of some phylogenetically distantly related species with the same ecotype were indistinguishable. Character evolution estimated parsimoniously using a phylogenetic tree suggests that the speciation among sympatric species is accompanied by ecological and morphological diversification. In addition, species coexistence of Mandarina is related to niche differentiation. The above findings suggest that ecological interactions among species contribute to the ecological and morphological diversification and radiation of these land snails in this depauperate environment.