The immunogenicity of human cardiac valve allografts in vitro and in vivo

Allogeneic transplantation has become an accepted method for the replacement of diseased organs and tissues. The concept of cardiac valve transplantation for the replacement of semilunar valves was introduced by Lam et al in 1952'. In about 1960 the first human cardiac valve allografts were implanted,,3, Human donor valves have become a good alternative for other valve substitutes (porcine valve prostheses and mechanical valves) because of their superior hemodynamic performance and the absence of post-operative thrombosis and thromboembolism. Further, these valves are relatively resistant to endocarditis and recipients of human donor valves do not require anticoagulant therapy. At this moment, the valve allografts are stored at heart valve banks. In 1995, 68 heart valve banks were known world-wide'. Before the introduction of cryopreservation techniques, human valve allografts were stored at 4"C in a nutrient medium containing an antibiotic solution, with a maximum storage time of 6 weeks5 ". These antibiotic-sterilized, "fresh wet-stored" allografts showed a better medium-term (7-10 years) clinical performance than glutaraldehyde-treated human valves"'. Alternative storage techniques (freeze-drying, irradiation) resulted in a shorter long-term graft survival compared to mechanical valves"" and a higher incidence of cusp rupture". The introduction of cryopreservation procedures offered long-term storage and improved the availability of the valves

Comparison of measured and predicted bandwidth of graded-index multimode fibres

Measurements of pulse spreading in three graded index fibers have been performed over an extensive range of wavelengths, including regions in which the index profiles become optimal and the bandwidths correspondingly high. The refractive index distributions and profile dispersion parameter have been measured and used in a ray-tracing algorithm in order to predict bandwidths. Comparison reveals that averaging processes on the index data are usually necessary to account for noncircularity of the fiber and small variations in the deduced profile caused by the wavelength dependence of the near-field intensity distribution. Results obtained by this means usually tend to slightly underestimate the true fiber bandwidth, while alpha-profile predictions always result in overestimates by about one order of magnitude. Remaining discrepancies between measured and predicted bandwidths are attributed to small variations of the index profiles along the fiber length

Effects of perinatal exposure to PCBs and dioxins on play behavior in Dutch children at school age

Polychlorinated biphenyls (PCBs) and dioxins are known as neurotoxic compounds that may modulate sex steroid hormones. Steroid hormones play a mediating role in brain development and may influence behaviors that show sex differences, such as childhood play behavior. In this study we evaluated the effects of perinatal exposure to environmental levels of PCBs and dioxins on childhood play behavior and whether the effects showed sex differences. As part of the follow-up to the Dutch PCB/dioxin study at school age, we used the Pre-School Activity Inventory (PSAI) to assess play behavior in the Rotterdam cohort (n = 207). The PSAI assesses masculine or feminine play behavior scored on three subscales: masculine, feminine, and composite. Prenatal exposure to PCBs was defined as the sum of PCB 118, 138, 153, and 180 in maternal and cord plasma and breast milk. For breast milk we measured additional PCBs as well as 17 dioxins. Respondents returned 160 questionnaires (age 7.5 years +/- 0.4). Effects of prenatal exposure to PCBs, measured in maternal and cord plasma, on the masculine and composite scales were different for boys and girls (p <.05). In boys, higher prenatal PCB levels were related with less masculinized play, assessed by the masculine scale (p(maternal) =.042; p(cord) =.001) and composite scale (p(cord) =.011), whereas in girls higher PCB levels were associated with more masculinized play, assessed by the composite scale (p(PCBmilk) =.028). Higher prenatal dioxin levels were associated with more feminized play in boys as well as girls, assessed by the feminine scale (p =.048). These effects suggest prenatal steroid hormone imbalances caused by prenatal exposure to environmental levels of PCBs, dioxins, and other related organochlorine compounds

Doppler colour flow imaging of fetal intracerebral arteries relative to fetal behavioural states in normal pregnancy

In 14 normally developing term fetuses, the relationship between the blood flow velocity waveforms at cerebral arterial level (internal carotid artery, anterior, middle and posterior cerebral artery) and fetal behavioural states was studied using Doppler colour flow imaging. Behavioural state dependent changes in absolute flow velocities occurred in all vessels, except for the middle cerebral artery. These changes suggest preferential blood flow to the left heart resulting in increased flow to the cerebrum during fetal behavioural state 2F (active sleep) when compared with fetal behavioural state 1F (quiet sleep). The middle cerebral artery supplies the neocerebrum. This developing part of the cerebrum does not seem to take part in the regulation of fetal behaviour. In the internal carotid artery, an inverse relationship between peak systolic velocity and fetal heart rate could be established, which can be explained by a shorter rapid filling phase at raised fetal heart rate according to the Frank-Starling Law

Satisfaction with penile appearance after hypospadias surgery: The patient and surgeon view

Purpose: We studied the degree of agreement between hypospadias patient and surgeon satisfaction with the cosmetic surgical result, and the relation between penile length, meatal position and patient satisfaction. Materials and Methods: Cosmetic and functional results in 35 boys with hypospadias were assessed, and a standardized questionnaire was completed by patients and surgeon. Results: There was hardly any agreement between patient and surgeon satisfaction with patient penile appearance. Patients were less satisfied than the surgeon. No significant correlation was noted between penile satisfaction and penile length. Patients with a retracted meatus were less satisfied with the meatal position than those with a glanular meatus. Of the 35 patients 4 underwent repeat surgery after our study. Conclusions: Hypospadias surgeons should explicitly ask if patients are satisfied and they should follow patients through adolescence

Effective contracting of uncertain performance outcomes : Allocating responsibility for performance outcomes to align goals across supply chain actors

This dissertation contributes to practice and literature by studying how organizations can effectively contract and sell uncertain performance outcomes. In Chapter 2, I study whether supplier shirking in response to outcome uncertainty can be mitigated by combining performance and behavior specification and evaluation. Based on the findings of this study, I advise purchasing managers to invest in the evaluation of perform

Characteristics and determinants of endurance cycle ergometry and six-minute walk distance in patients with COPD

BACKGROUND: Exercise tolerance can be assessed by the cycle endurance test (CET) and six-minute walk test (6MWT) in patients with Chronic Obstructive Pulmonary Disease (COPD). We sought to investigate the characteristics of functional exercise performance and determinants of the CET and 6MWT in a large clinical cohort of COPD patients. METHODS: A dataset of 2053 COPD patients (43% female, age: 66.9 ± 9.5 years, FEV(1)% predicted: 48.2 ± 23.2) was analyzed retrospectively. Patients underwent, amongst others, respiratory function evaluation; medical tests and questionnaires, one maximal incremental cycle test where peak work rate was determined and two functional exercise tests: a CET at 75% of peak work rate and 6MWT. A stepwise multiple linear regression was used to assess determinants. RESULTS: On average, patients had impaired exercise tolerance (peak work rate: 56 ± 27% predicted, 6MWT: 69 ± 17% predicted). A total of 2002 patients had CET time of duration (CET-T(end)) less than 20 min while only 51 (2.5%) of the patients achieved 20 min of CET-T(end) . In former patients, the percent of predicted peak work rate achieved differed significantly between men (48 ± 21% predicted) and women (67 ± 31% predicted). In contrast, CET-T(end) was longer in men (286 ± 174 s vs 250 ± 153 s, p < 0.001). Also, six minute walking distance (6MWD) was higher in men compared to women, both in absolute terms as in percent of predicted (443 m, 67%predicted vs 431 m, 72%predicted, p < 0.05). Gender was associated with the CET-T(end) but BMI, FEV(1) and FRC were related to the 6MWD highlighting the different determinants of exercise performance between CET and 6MWT. CONCLUSIONS: CET-T(end) is a valuable outcome of CET as it is related to multiple clinical aspects of disease severity in COPD. Gender difference should temper the interpretation of CET

Armed Attack in Cyberspace:Clarifying and Assessing when Cyber-Attacks Trigger the Netherlands' Right of Self-Defence

Whilst Article 51 of the UN Charter indicates that an ‘armed attack’ may trigger a State’s inherent right of individual or collective self-defence, the purport of armed attack remains a matter of interpretation and qualification. Moreover, actions carried out in (or through) cyberspace have caused the impetus for another debate: whether and when cyber-attacks can be qualified as an armed attack. To improve the notion of self-defence and contribute to the jus ad bellum (international law on the use of transnational force), more clarification as to what constitutes an armed attack in cyberspace is necessary. The main aim of the paper is to propose a tangible guideline that outlines when cyber-attacks – perpetrated solely in or through cyberspace and not in conjunction with conventional military attacks – can be qualified as an armed attack

Inclusion body myositis. Clinical aspects

Sporadische inclusion body myositis (IBM) is een van de meest voor voorkomende verworven spierziekte die ontstaat na het 50e levensjaar. In dit proefschrift worden de klinische aspecten van sporadische IBM beschreven. Uit de studie met betrekking tot het natuurlijk beloop blijkt dat de ziekte niet levensverkortend is, maar dat de doodsoorzaken bij sporadische IBM wel verschillen ten opzichte van een voor de leeftijd gecorrigeerde populatie. De aard en frequentie van slikstoornissen worden beschreven, alsmede de potentiele betrokkenheid van het hart. Door middel van MRI's van skeletspieren is een voor sporadische IBM specifiek patroon van afwijkingen beschreven. Ten slotte is aangetoond dat TREX1 mutaties geen rol spelen in het ontstaan van de ziekte.UBL - phd migration 201