883 research outputs found
Interferons, properties and applications
The main theme of this thesis is the clinical evaluation of interferon.
From the biology of the interferon system and animal experiments it
can be expected that exogenous interferon will exert its optimum effect
when used to prevent acute infections or to modulate chronic infections.
Therefore, we administered interferon to patients with chronic
hepatitis B virus infection (chapter 5) and to renal transplant recipients,
in whom viral infections occur frequently in the first months
after transplantation (chapter 6).
The other studies in this thesis are directly related to the problems
we met in the clinical studies. We wanted to study interferon in
an animal renal transplantation model. For us the most obvious choice
was the rat. However, little was known about the production and characterization
of rat interferon. Chapter 2 describes our experiences
with rat interferon.
While we were well underway with the study in renal transplant recipients,
we were contacted by Martin Hirsch, who was conducting a
similar trial in Boston. Some of his patients receiving 3 x 106 U HLI
every other day showed severe bone marrow depression. We had no such
problem in our trial, but we used another type of interferon: HFI.
For this reason we started a study on the t'oxicity of interferons for
bone marrow in vitro
Poincar\'e and sl(2) algebras of order 3
In this paper we initiate a general classification for Lie algebras of order
3 and we give all Lie algebras of order 3 based on
and the Poincar\'e algebra in four-dimensions. We then
set the basis of the theory of the deformations (in the Gerstenhaber sense) and
contractions for Lie algebras of order 3.Comment: Title and presentation change
Construction of an isotropic cellular automaton for a reaction-diffusion equation by means of a random walk
We propose a new method to construct an isotropic cellular automaton
corresponding to a reaction-diffusion equation. The method consists of
replacing the diffusion term and the reaction term of the reaction-diffusion
equation with a random walk of microscopic particles and a discrete vector
field which defines the time evolution of the particles. The cellular automaton
thus obtained can retain isotropy and therefore reproduces the patterns found
in the numerical solutions of the reaction-diffusion equation. As a specific
example, we apply the method to the Belousov-Zhabotinsky reaction in excitable
media
Generalization of the Gell-Mann formula for sl(5, R) and su(5) algebras
The so called Gell-Mann formula expresses the Lie algebra elements in terms
of the corresponding Inonu-Wigner contracted ones. In the case of sl(n, R) and
su(n) algebras contracted w.r.t. so(n) subalgebras, the Gell-Mann formula is
generally not valid, and applies only in the cases of some algebra
representations. A generalization of the Gell-Mann formula for sl(5,R) and
su(5) algebras, that is valid for all representations, is obtained in a group
manifold framework of the SO(5) and/or Spin(5) group
Culture of graft-infiltrating cells from cryopreserved endomyocardial biopsies
Graft-infiltrating cells can be cultured from fresh endomyocardial biopsies (EMB) taken after heart transplantation to determine their growth patterns, phenotypic composition, and functional characteristics for clinical or scientific purposes. In this study we investigated whether graft-infiltrating cells can also be cultured successfully after cryopreservation of these EMB. Three different cryopreservation methods were used. One method gave successful growth in 100% of the cases (n = 6): The biopsy fragments were preincubated in 10% vol/vol dimethyl sulfoxide during 5 min at O°C, frozen to -70°C at approximately 1°C per minute, and subsequently immersed and stored in liquid nitrogen. Thawing was performed rapidly in water at 37°C. In addition, the effect of cryopreservation on cell surface phenotype and donor-specific cytotoxicity of these graft-infiltrating cells was analyzed. When compared to cultures of nonfrozen control biopsies, both qualities remained constant in most cases, although a variation in CD4+/CD8+ cell ratio was observed in 33% of these cultures. However, when nonfrozen fragments of size-matched biopsies were cultured separately, a similar variation in phenotype was noted, indicating that this phenomenon can be attributed to sampling variation and not to the cryopreservation procedure. The present findings suggest that it is no longer required to culture fresh (nonfrozen) post-transplant EMB to propagate graft-infiltrating cells: Culturing can be limited to cryopreserved EMB that are selected retrospectively, depending on actual clinical or scientific interests. Besides greatly facilitating the long-term monitoring of heart transplant recipients, this also means a substantial decrease in cost and work load for laboratories involved in heart transplantation
Living Donor Kidney Transplantation Should Be Promoted among "elderly" Patients
Background. Age criteria for kidney transplantation have been liberalized over the years resulting in more waitlisted elderly patients. What are the prospects of elderly patients on the waiting list? Methods. Between 2000 and 2013, 2622 patients had been waitlisted. Waiting time was defined as the period between dialysis onset and being delisted. Patients were categorized according to age upon listing: 64 years. Furthermore, the influence of ABO blood type and panel reactive antibodies on outflow patterns was studied. Results. At the end of observation (November 2017), 1957 (75%) patients had been transplanted, 333 (13%) had been delisted without a transplantation, 271 (10%) had died, and 61 (2%) were still waiting. When comparing the age categories, outflow patterns were completely different. The percentage of patients transplanted decreased with increasing age, while the percentage of patients that had been delisted or had died increased with increasing age, especially in the population without living donor. Within 6 years, 93% of the population 55 years, 39% received a living donor kidney, while >50% of patients without a living donor had been delisted/died. Multivariable analysis showed that the influence of age, ABO blood type, and panel reactive antibodies on outflow patterns was significant, but the magnitude of the influence of the latter 2 was only modest compared with that of age. Conclusions. "Elderly" (not only >64 y but even 55-64 y) received a living donor kidney transplantation less often. Moreover, they cannot bear the waiting time for a deceased donor kidney, resulting in delisting without a transplant in more than half the population of patients without a living donor. Promoting living donor kidney transplantation is the only modification that improves transplantation and decreases delisting/death on the waiting list in this population
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