3 research outputs found
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
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
Supplementary data for: Missed Diagnoses and Health Problems in Adults With Prader-Willi Syndrome: Recommendations for Screening and Treatment
Context: Prader-Willi syndrome (PWS) is a complex hypothalamic disorder, combining
hyperphagia, hypotonia, intellectual disability, and pituitary hormone deficiencies.
Annual mortality of patients with PWS is high (3%). In half of the patients, the cause of
death is obesity related and/or of cardiopulmonary origin. Health problems leading to
this increased mortality often remain undetected due to the complexity and rareness of
the syndrome.
Objective: To assess the prevalence of health problems in adults with PWS retrospectively.
Patients, Design, and Setting: We systematically screened 115 PWS adults for
undiagnosed health problems. All patients visited the multidisciplinary outpatient clinic
for rare endocrine syndromes at the Erasmus University Medical Center, Rotterdam,
Netherlands. We collected the results of medical questionnaires, interviews, physical xaminations, biochemical measurements, polygraphy, polysomnography, and
radiology.
Main outcome measures: Presence or absence of endocrine and nonendocrine
comorbidities in relation to living situation, body mass index, genotype, and demographic
factors.
Results: Seventy patients (61%) had undiagnosed health problems, while 1 in every
4 patients had multiple undiagnosed health problems simultaneously. All males and
93% of females had hypogonadism, 74% had scoliosis, 18% had hypertension, 19% had
hypercholesterolemia, 17% had type 2 diabetes mellitus, and 17% had hypothyroidism.
Unfavorable lifestyles were common: 22% exercised too little (according to PWS criteria)
and 37% did not see a dietitian.
Conclusions: Systematic screening revealed many undiagnosed health problems in
PWS adults. Based on patient characteristics, we provide an algorithm for diagnostics
and treatment, with the aim to prevent early complications and reduce mortality in this
vulnerable patient group