Acceptance of related and unrelated cardiac allografts in neonatally tolerized mice is cardio-specific and transferable by regulatory CD4+ T cells

BACKGROUND

Non-donor-specific cardiac allograft acceptance is induced in C3H/He (C3H; H-2k) recipients injected as neonates with allogeneic BALB/c (BALB; H-2d) fetal liver cells (FLC). This occurs despite intact reactivity to donor-type and third-party alloantigens in in vitro assays and skin transplants. To investigate a role for regulatory T cells, we performed adoptive transfer studies and specifically assessed CD4+ and CD4- T cells.

METHODS

Three cell populations (splenocytes, CD4+, CD4-) derived from neonatally-treated mice with accepted C57BL/6 (B6; H-2b) third-party cardiac grafts were adoptively transferred into sub-lethally-irradiated C3H mice. Reconstituted mice were challenged with B6 cardiac grafts, B6 skin grafts, or unrelated cardiac grafts. Separated cells were assessed in vitro.

RESULTS

B6, BALB, and NZW (H-2z) graft acceptance was transferred by unfractionated splenocytes. CD4+ cells transferred B6 graft acceptance (85% survival > 100 days). CD4- cells, unfractionated cells from naive or only irradiated mice, and unfractionated cells from neonatally-treated non-transplanted C3H mice rejected grafts within 35 days. No inoculum induced skin graft acceptance. Co-cultured assays confirmed the suppressive function of CD4+ cells in vitro.

CONCLUSIONS

Cardiac allograft acceptance in our model is regulated by CD4+ cells. The regulatory cell population is induced by the cardiac graft itself and mediates in vivo cardiac graft acceptance in a tissue-specific but not donor-strain-specific manner.

The paradox of health care

The term "paradox" signifies a contradiction of some sort. Modern health care appears to be rich in contradictions, and it is claimed to be paradoxical in a number of ways. In particular health care is held to be a paradox itself: it is supposed to do good, but is accused of doing harm. The objective of this article is to investigate whether the concept of paradox can serve as a framework for analysing pressing problems in modern health care. To pursue this, three distinctive levels of paradox are identified: resolvable paradoxes, antinomies and aporias. The analysis reveals that when facing the challenges of modern health care the focus of attention should be to resolve the resolvable paradoxes, to acknowledge the antinomies and to learn to live with the aporias.

GABA(A)-receptor expression in glioma cells is triggered by contact with neuronal cells

The expression of functional GABA(A)-receptors in glioma cells correlates with low malignancy of tumours and cell lines from glioma lack these receptors. Here we show that contact with neurons induces the expression of functional GABA(A)-receptors. C6 and F98 glioma cell lines were labelled by recombinant expression of enhanced green fluorescent protein injected into rat brain and studied in acute slices after two to three weeks of tumour growth. The cells responded to GABA or the specific agonist, muscimol with a current typical for GABA(A)-receptors, as studied with the patch-clamp technique. To get insight into the mechanism of GABA(A) receptor induction, the C6 or F98 cells were co-cultured with neurons, astrocytes, oligodendrocytes and microglia. Glioma cells expressed functional GABA(A) receptors within 24 h only in cultures where physical contact to neurons occurred. Activation of GABA(A)-receptors in the co-cultures attenuated glioma cell metabolism while blockade of the receptors increased metabolism. We conclude that with this form of interaction, neurons can influence tumour behaviour in the brain.

Production of selenomethionine-labelled proteins using simplified culture conditions and generally applicable host/vector systems

The amino acid analogue selenomethionine (SeMet) is shown to be efficiently incorporated into recombinant proteins expressed in Escherichia coli grown in a simple minimal medium without the addition of synthetic amino acids. Furthermore, satisfactory SeMet incorporation is obtained with a methionine-prototrophic strain transformed with commonly used vector systems. As examples, purified tryparedoxin 1 from Crithidia fasciculata, alkylhydroperoxide reductase (AhpC) from Mycobacterium marinum and the 16-kDa antigen from M. tuberculosis are shown to be efficiently labelled with SeMet, using the culture conditions and the host/vector systems described here. Enzymatic analysis reveals no differences between native and SeMet-labelled tryparedoxin 1 enzyme. Both proteins yield crystals under similar conditions. The culture conditions and host vector systems described greatly facilitate selenium-labelling of proteins for 3-D structure determination.

Complexity of the concept of disease as shown through rival theoretical frameworks

The concept of disease has been the subject of a vast, vivid and versatile debate. Categories such as "realist", "nominalist", "ontologist", "physiologist", "normativist" and "descriptivist" have been applied to classify disease concepts. These categories refer to underlying theoretical frameworks of the debate. The objective of this review is to analyse these frameworks. It is argued that the categories applied in the debate refer to profound philosophical issues, and that the complexity of the debate reflects the complexity of the concept itself: disease is a complex concept, and does not easily lend itself to definition.

The technological invention of disease

Technology has come to play a profound role in medicine since the middle of the 19th century, and many scholars have analysed the role of technology in medicine. Parallel to this development there has been a comprehensive debate on the concept of disease. This article combines these fields and investigates the influence of technology on the concept of disease. With reference to the literature it tries to elaborate an explicit account of the constitutive role of technology in relation to the concept of disease. It will be argued that technology constitutes the concept of disease in three profound ways. Firstly, technology provides the physiological, biochemical, and biomolecular entities that are applied in defining diseases. Secondly, it establishes the way we try to gain knowledge of disease and the way we recognise disease in practice. Technology constitutes the signs, markers and end points that define disease entities and it strongly influences the explanatory models of disease as well as medical taxonomy. Thirdly, technology establishes how we act towards disease: thorough diagnosis and treatment technology establishes the actions that constitute the concept of disease. Altogether, this constitutive technological influence on the concept of disease is considered as a technological invention of disease.

Early experience with a quadrileaflet stentless mitral valve

BACKGROUND

Presently no ideal prosthesis for mitral valve replacement exists. The quadrileaflet mitral valve (SJM-Quattro-MV; St. Jude Medical, Inc, St. Paul, MN) is a chordally supported stentless bioprosthesis. Due to its specific geometry it seems to be particularly suited for mitral valve replacement.

METHODS

From March 1999 to October 2000, 12 patients (ages 71+/-2 years) received the SJM-Quattro-MV. Six patients suffered from valvular stenosis and 6 patients from incompetence. Preoperatively, all patients were in New York Heart Association functional class III, with left ventricular ejection fraction amounts of 54%+/-17%.

RESULTS

Eleven patients received a medium size SJM-Quattro-MV and one patient received a large size SJM-Quattro-MV. Cross-clamp time was 99.8+/-4.9 minutes. Additional procedures were coronary artery bypass grafting (n = 3) and left atrial microwave ablation (n = 2). Postoperative mortality (n = 1) was procedure related. At follow-up of 11.6+/-5.4 months, all patients were well, the transvalvular pressure gradient was 5.0+/-1.4 mm Hg, and the effective orifice area 2.7+/-0.2 cm2.

CONCLUSIONS

Our preliminary experiences with the SJM-Quattro-MV presented good clinical results and promoted an optimistic way of thinking about the further development of these valve prostheses.

[Physician as a body technician]

"The physician as a technician" is a metaphor for a significant critique of modern medicine. This article approaches some of these critiques. The notion of medicine as an art is sometimes used to remind us of and in praise of the non-technical aspects of medicine. After indicating some difficulties with modern conceptions of medicine as art, I bring in the ancient concept of art, "téchnê", arguing that it avoids some of the difficulties of the modern art concept. Téchnê actually integrates the scientific, technical and normative aspects of medicine and gives a positive interpretation of the claim that the physician has become a technician. The concept provides medicine with a fruitful framework for understanding both technology and philosophy.

Time course of osteocalcin, bone-specific alkaline phosphatase, and C-terminal procollagen peptide during callus distraction

This study involved 15 patients who were undergoing extremity lengthening by callus distraction. Blood samples and radiographs of the callus distraction segment were obtained before surgery, every 2 weeks during the distraction phase, and every 4 weeks between the end of distraction and removal of the fixator. A digital radiograph analysis system was used to determine the radiographic density of the callus distraction segments. In addition, the serum parameters osteocalcin, bone-specific alkaline phosphatase, and C-terminal procollagen peptide (PICP) were evaluated. The radiographic density was constant during the distraction phase, but increased logarithmically during the consolidation period. Similar kinetics were observed for osteocalcin, with an average coefficient of correlation between these two parameters of 0.66+/-0.15. PICP levels rose rapidly after surgery and increased further during the consolidation period. Serum levels of bone-specific alkaline phosphatase were not uniform between patients, and there was no correlation to the kinetics of radiographic density or the other serum parameters. The similarity between radiographic density and osteocalcin kinetics, as well as the rapid postoperative increase in PICP, imply that further information may be obtained about osteoneogenesis from the study of these two serum parameters.

Structures of Tryparedoxins Revealing Interaction with Trypanothione

Tryparedoxins (TXNs) catalyse the reduction of peroxiredoxin-type peroxidases by the bis-glutathionyl derivative of spermidine, trypanothione, and are relevant to hydroperoxide detoxification and virulence of trypanosomes. The 3D-structures of the following tryparedoxins are presented: authentic tryparedoxin1 of Crithidia fasciculata, CfTXN1; the his-tagged recombinant protein, CfTXN1H6; reduced and oxidised CfTXN2, and an alternative substrate derivative of the mutein CfTXN2H6-Cys44Ser. Cys41 (Cys40 in TXN1) of the active site motif 40-WCPPCR-45 proved to be the only solvent-exposed redox active residue in CfTXN2. In reduced TXNs, its nucleophilicity is increased by a network of hydrogen bonds. In oxidised TXNs it can be attacked by the thiol of the 1N-glutathionyl residue of trypanothione, as evidenced by the structure of 1N-glutathionylspermidine-derivatised CfTXN2H6-Cys44Ser. Modelling suggests Arg45 (44), Glu73 (72), the Ile110 (109) cis-Pro111 (110)-bond and Arg129 (128) to be involved in the binding of trypanothione to CfTXN2 (CfTXN1). The model of TXN-substrate interaction is consistent with functional characteristics of known and newly designed muteins (CfTXN2H6-Arg129Asp and Glu73Arg) and the 1N-glutathionyl-spermidine binding in the CfTXN2H6-Cys44Ser structure.

On the value-ladenness of technology in medicine

The objective of this article is to analyse the value-ladenness of technology in the context of medicine. To address this issue several characteristics of technology are investigated: i). its interventive capacity, ii). its expansiveness and iii). its influence on the concept of disease, iv). its generalising character, v). its independence of the subjective experience of the patient. By this analysis I hope to unveil the double face of technology: Technology has a Janus-face in modern medicine, and the opposite of its factual face is evaluative.

Identification of the familial cylindromatosis tumour-suppressor gene

Familial cylindromatosis is an autosomal dominant genetic predisposition to multiple tumours of the skin appendages. The susceptibility gene (CYLD) has previously been localized to chromosome 16q and has the genetic attributes of a tumour-suppressor gene (recessive oncogene). Here we have identified CYLD by detecting germline mutations in 21 cylindromatosis families and somatic mutations in 1 sporadic and 5 familial cylindromas. All mutations predict truncation or absence of the encoded protein. CYLD encodes three cytoskeletal-associated-protein-glycine-conserved (CAP-GLY) domains, which are found in proteins that coordinate the attachment of organelles to microtubules. CYLD also has sequence homology to the catalytic domain of ubiquitin carboxy-terminal hydrolases (UCH).

Imaging of tumour neovasculature by targeting the TGF-beta binding receptor endoglin

In vivo imaging of endothelial markers in intact tumour neovasculature would have applications in assessing the efficacy of anti-angiogenic agents in clinical trials. Although a variety of different endothelial markers have been described, few have been evaluated as imaging markers. The transforming growth factor-beta (TGF-beta) binding receptor endoglin is a proliferation-associated endothelial marker. We hypothesised that endoglin would be an ideal target for imaging since it is strongly upregulated in proliferating endothelial cells of the tumour neovasculature. We used a radiolabelled monoclonal anti-endoglin antibody and compared its neovascular binding, accumulation and in vivo behaviour to an isotype-matched control IgG(2a). Our data show that the probe binds specifically and rapidly within minutes in vivo and that correlative autoradiography and immunohistology support the in vivo imaging findings. Imaging of abundantly expressed endothelial targets circumvents delivery barriers normally associated with other tumour targeting strategies, and can potentially be used to quantitate molecular angiogenic markers.

Linkage and LOH studies in 19 cylindromatosis families show no evidence of genetic heterogeneity and refine the CYLD locus on chromosome 16q12-q13

Familial cylindromatosis is an autosomal dominant predisposition to multiple neoplasms of the skin appendages. The susceptibility gene has previously been mapped to chromosome 16q12-q13 and has features of a recessive oncogene/tumour suppressor gene. We have now evaluated 19 families with this disease by a combination of genetic linkage analysis and loss of heterozygosity in cylindromas from affected individuals. All 15 informative families show linkage to this locus, providing no evidence for genetic heterogeneity. Recombinant mapping has placed the gene in an interval of approximately 1 Mb. There is no evidence, between families, of haplotype sharing that might be indicative of common founder mutations.

Effect of topical tazarotene in the treatment of congenital ichthyoses

The clinical efficacy and tolerability of the topical receptor-selective retinoid tazarotene in the treatment of congenital ichthyoses was investigated. Twelve consecutive patients with different forms of congenital ichthyosis were enrolled in an open, non-randomized, intraindividually controlled, half-side pilot study. Diagnoses were X-linked recessive ichthyosis, non-erythrodermic autosomal recessive lamellar ichthyosis, autosomal dominant ichthyosis vulgaris and ichthyosis bullosa of Siemens (IBS). Tazarotene 0.05% gel was applied unilaterally daily on a defined body area measuring 10% of the body surface area. The contralateral side was treated with an ointment containing 10% urea. After 14 days, application frequency was reduced to three times a week, and stopped after another 2 weeks. The follow-up period was 3 months. Reduction in scaling and roughness was used to assess the clinical response in the tazarotene-treated area compared with the control area. Clinical and laboratory assessments were performed every 14 days during the trial. Unilateral improvement in favour of the tazarotene-treated side was observed in nine of 12 patients (75%). Four patients (33%) achieved an excellent response and four (33%) achieved a good response. No therapeutic effect was seen in patients with IBS. The remission persisted during the reduction phase and after discontinuation for up to 2 months. Local irritation in three patients was the only side-effect detectable. Short-term topical application of tazarotene 0.05% gel is a very effective and well-tolerated treatment modality in different forms of congenital ichthyoses and may be an alternative to systemic retinoid therapy.

[Multifocal malignant transformation of extreme fibromatosis with pulmonary involvement]

We report on the case of a 40-year old patient with extreme neurofibromatosis with severe kyphoskoliosis and deformation of the thorax. The patient died from malignant transformation which occurred multifocally with extensive pulmonary metastases. The well-known thoracic manifestations of neurofibromatosis are reviewed.

[Psycho-neurogenic factors as a cause of life-threatening arrhythmias]

Tachyarrhytmias often occur during increased emotional arousal or mental excitation. The implantable cardioverter defibrillator (ICD) allows the exact documentation of arrhythmic episodes and their time of onset. Therefore, the type of arrhythmia can be differentiated as well as the circumstances surrounding the event. These features allow the assessment of possible psychic arrhythmogenic factors in the natural environment. We analyzed the ICD-protocols of three male patients (in ages between 60 and 68), whose devices had successfully terminated a ventricular tachycardia and compared the onset of the episodes with the patients' detailed descriptions of the corresponding life situations. The analysis of the circumstances at the time of arrhythmia-onset revealed a relationship between the occurrence of life-threatening arrhythmias in natural environment and emotional stress. The stressors could be defined as situations of increased vulnerability leading to sympathetic excitation. The induction of tachyarrhythmia was promoted in case 1 by acute psychic distress (public speaking), by the increasing panic-attack-like vicious circle of the cognitive anticipation of an unfavorable outcome (case 2), and an adverse anger reaction superimposed on persistent feelings of help- and hopelessness (case 3). These findings are in line with several experimental and epidemiological studies providing evidence for a relationship between psychic arousal and the induction of tachyarrhythmias. The knowledge of emotional and mental factors that function as a trigger for arrhythmias may lead to new therapeutic approaches in the prevention of sudden cardiac death.