Cost-effectiveness assessment of three components of the bovine tuberculosis surveillance system by intradermal tuberculin testing in French cattle farms by a scenario tree approach

In most officially bovine tuberculosis (bTB)-free countries, bTB has not been fully eradicated. Costly and time-consuming surveillance and control measures are therefore still in place to control this infection. An officially bTB-free status, both at the national and at the herd level, influences whether and when animals can be sold. Thus, this infection is still an economic issue, justifying measures towards its eradication. An evaluation of the cost-effectiveness of such measures would be highly useful, especially to optimise the costs of control measures and their adaptation to a local epidemiological context. We evaluated the cost-effectiveness of three mandatory surveillance protocols currently used in France by herd type (type of production, size, and turnover of the herd) under French field conditions. The first protocol ("strict") implies the direct slaughter and post-mortem analyses of any intradermal cervical tuberculin test (ICT) reactor, and negative results to a second intradermal cervical comparative tuberculin test (ICCT) to regain bTB-free status of the herd. In the second protocol ("compliant quick-path") bTB-free status can be regain if post-mortem analyses of reactors to the first ICT are negative. In the third protocol ("compliant slow-path"), ICCT-reactive animals are tested using the interferon gamma assay; the results of this test influence the path of further investigation. We built scenario trees for each of these protocols at the animal level. They allowed us to estimate herd sensitivity and the total cost of each protocol by herd type. The protocols could be ordered by decreasing herd sensitivity and cost, regardless of the herd type, as follows: strict protocol, compliant quick-path protocol, and compliant slow-path protocol. We calculated a cost-effectiveness index to evaluate the cost-effectiveness of each protocol. The strict protocol was never the most cost-effective, regardless of herd type, due to higher costs relative to the other protocols, despite better herd sensitivity. We found the compliant quick-path to be the most cost-effective protocol for big beef, big dairy, and mixed herds. The compliant slow-path was the most cost-effective for small-scale beef and dairy herds. All differences were significant. This comparison of the cost-effectiveness of the protocols by herd type could help authorities to choose the most suitable protocol in the investigation of suspected cases, depending on the herd type, but could be improved by accounting for important sociological data, such as the acceptability of the protocols.

[Motivations for a consultation before adoption: A multicenter study]

INTRODUCTION

While the number of international adoptions in France is decreasing, adopted children are older and in poorer health than they used to be. This phenomenon has resulted in an increase in the demand for preadoption consultations over the past several years. This study analyses the reasons for these consultations.

METHOD

Prospective multicenter study conducted from 1 January to 31 December 2013.

RESULTS

Ten centers contributed to the study, i.e., 196 preadoption consultations. Seeking medical advice was the reason for 88% of the consultations, whether the advice was based on the study of an identified child's medical file (32%) or a country's healthcare characteristics, whether the country was identified (34%) or not (23%). In 6% of cases, the motive for preadoption consultations was social and familial, and in the last 5% it was to obtain general information about adoption and its procedures. In more than 40% of the cases, whether the child or the country identified, Russia is the subject of the consultation because of the complexity of the files and because of the dreaded but rarely mentioned fetal alcohol syndrome.

CONCLUSION

The deterioration of adopted children's health is an additional worry for future adoption applicants. To provide them with the best information possible without making choices for them, specialists should have substantial experience in adoption before going into these preadoption consultations.

Ecological gradients driving the distribution of four Ericaceae in boreal Quebec, Canada

Understory species play a significant role in forest ecosystem dynamics. As such, species of the Ericaceae family have a major effect on the regeneration of tree species in boreal ecosystems. It is thus imperative to understand the ecological gradients controlling their distribution and abundance, so that their impacts can be taken into account in sustainable forest management. Using innovative analytical techniques from landscape ecology, we aimed to position, along ecological gradients, four Ericaceae found in the boreal forest of Quebec (Canada) (Rhododendron groenlandicum, Kalmia angustifolia, Chamaedaphne calyculata, and Vaccinium spp), to regionalize these species into landscape units relevant to forest management, and to estimate the relative importance of several ecological drivers (climate, disturbances, stand attributes, and physical environment) that control the species distribution and abundance. We conducted our study in boreal Quebec, over a study area covering 535,355 km². We used data from 15,339 ecological survey plots and forest maps to characterize 1422 ecological districts covering the study region. We evaluated the relative proportion of each ericaceous species and explanatory variables at the district level. Vegetation and explanatory variables matrices were used to conduct redundancy, cluster, and variation partitioning analyses. We observed that ericaceous species are mainly distributed in the western part of the study area and each species has a distinct latitudinal and longitudinal gradient distribution. On the basis of these gradients, we delimited 10 homogeneous landscape units distinct in terms of ericaceous species abundance and environmental drivers. The distribution of the ericaceous species along ecological gradients is closely related to the overlaps between the four sets of explanatory variables considered. We conclude that the studied Ericaceae occupy specific positions along ecological gradients and possess a specific abundance and distribution controlled by the integration of multiple explanatory variables.

Health care support issues for internationally adopted children: a qualitative approach to the needs and expectations of families

BACKGROUND

Families of internationally adopted children may face specific problems with which general practitioners (GPs) may not be familiar. The aim of the study was to explore problems faced by families before, during and after the arrival of their internationally adopted child and to assess the usefulness of a specific medical structure for internationally adopted children, which could be a resource for the GP.

METHODOLOGY/PRINCIPAL FINDINGS

We conducted a qualitative study using individual semistructured guided conversations and interviewed 21 families that had adopted a total of 26 children internationally in the Puy de Dome department, France, in 2003. Quantitative data were used to describe the pathologies diagnosed and the investigations performed.Our study showed that the history of these families, from the start of the adoption project to its achievement, is complex and warrants careful analysis. Health-care providers should not only consider the medical aspects of adoption, but should also be interested in the histories of these families, which may play a role in the forming of attachments between the adoptee and their adoptive parents and prevent further trouble during the development of the child. We also showed that adoptive parents have similar fears or transient difficulties that may be resolved quickly by listening and reassurance. Most such families would support the existence of a specific medical structure for internationally adopted children, which could be a resource for the general practitioner. However, the health-care providers interviewed were divided on the subject and expressed their fear that a special consultation could be stigmatizing to children and families.

CONCLUSIONS/SIGNIFICANCE

A specific consultation with well-trained and experienced practitioners acting in close collaboration with GPs and paediatricians may be of help in better understanding and supporting adopted children and their families.

Phase I/II study of the association of sorafenib and temozolomide (extended schedule) in patients with metastatic melanoma: A new clinical response profile with massive tumor necroses

9062

Background: Recent progress in melanoma research identified a wide variety of different melanomas in term of biology, clinical behavior and chemosensitivity profiles. This phase I/II study of association of sorafenib (SOR) and temozolomide (TMZ) evaluates the safety and efficacy of this association in patients with metastatic melanoma and tries to correlate clinical responses to early biological and imaging parameters. We report the ph I results and preliminary results of the ph II (still recruiting pts). Methods: Safety was the primary objective of the phase I and three escalating dose levels were tested. Primary objective of the phase II is PFS at 12 weeks and 32 patients were recruited at the recommended (45 planned). Secondary objectives evaluate tumour vascularization by dynamic contrast enhanced ultrasonography (DCE-US), PK profile of TMZ, number and function of circulating lymphocytes, melanoma RNA expression profiles and mutational status (BRAF, NRAS, c-KIT, PTEN, PI3K, βcat), circulating endothelial and progenitor cells. Results: 13 evaluable pts were included in the phase I. The recommended doses are SOR: 400 mg bid and TMZ: 150 mg/m2 /d every other week. Toxicity was manageable. SOR did not influence TMZ PK. RECIST evaluation showed 1 CR (+ 12 months), 1 PR (+ 13 months), 3 SD, 8 PD. Among the 23 evaluable pts included in the phase II, 1 PR, 11 SD and 11 PD were observed. Five pts presented rapid and massive metastases necrosis with obvious tumour cavitation on CT which is very unusual during the course of melanoma treatment. Devascularization seen on DCE-US after 1 month was predictive of tumour response. Integrated correlative biological parameters are being analyzed and will be presented. Conclusions: SOR+TMZ association is well tolerated and gives promising results in some patients with metastatic melanoma. Unexpected major tumour necrosis has been observed in 5 patients. Early tumour devascularization observed by DCE-US seems predictive for tumour response. Extensive biological studies are being performed and might give useful clues allowing the identification of melanoma subtypes that are sensitive to this treatment regimen.

No significant financial relationships to disclose.

Varicelle compliquée d’une endocardite à streptocoque A : à propos d’une observation

Although varicella is most often a benign and self-limited disease of childhood, it can be associated with a variety of serious and potential lethal complications. Especially, the incidence of severe infectious complications caused by group A streptococci has been increasing over the last years. We report the case of a previously healthy young boy with an aortic bicuspidy who developed a varicella complicated by endocarditis due to group A streptococcus, and a haemophagocytic syndrome. A favorable outcome was obtained after an early valvular replacement and 6 weeks of intravenous antibiotics.

Naloxone for shock

BACKGROUND

There is pre-clinical evidence, involving several animal species, suggesting that opioid peptides play a role in the physiopathology of shock (endotoxic, hypovolemic, cardiogenic, spinal, anaphylactic). Many case reports have suggested that naloxone (an opiate antagonist) might be an effective treatment for shock in humans, but others have not supported such a point of view. This controversy led us to undertake a meta-analysis of the available evidence on the efficacy of naloxone as a treatment measure of shock in humans.

OBJECTIVES

To evaluate the effectiveness and safety of naloxone in human shock and to estimate the methodological quality of the clinical trials.

SEARCH STRATEGY

Computerized bibliographic search up to December 2002, review of references of all papers found on the subject and contact with primary investigators of eligible studies.

SELECTION CRITERIA

Randomized controlled trials evaluating naloxone in human shock, regardless of the patient's age (adult, child or neonate).

DATA COLLECTION AND ANALYSIS

Three independent reviewers extracted data on study design, intervention, outcome and methodological quality.

MAIN RESULTS

Three independent readers reviewed 80 human publications and selected six clinical trials. Overall agreement on study selection was perfect (concordance: 100%). This meta-analysis includes six studies involving 126 patients with septic, cardiogenic, hemorrhagic or spinal shock. Naloxone therapy was associated with statistically significant hemodynamic improvement (odds ratio 0.24; 95% confidence interval [95%CI] 0.09-0.68). The mean arterial pressure was significantly higher in the naloxone groups than in the placebo groups (weighted mean difference: +9.33 mmHg; 95%CI 7.07-11.59). No heterogeneity was found for this outcome. The death rate was lower in the naloxone group (odds ratio 0.59; 95%CI 0.21-1.67) but this was consistent with the play of chance. A significant heterogeneity for the latter outcome was detected (p<0.05).

REVIEWER'S CONCLUSIONS

Naloxone improves blood pressure, especially mean arterial blood pressure. However, the clinical usefulness of naloxone to treat shock remains to be determined, and additional randomized controlled trials are needed to assess its usefulness.

The Heartmate II: design and development of a fully sealed axial flow left ventricular assist system

Our group is developing the control and power transmission components required to implement a permanent and fully sealed left ventricular assist system (LVAS). Starting with the percutaneously powered HeartMate II blood pump, our development efforts are focused in the following areas: a complete redesign of the transcutaneous energy transmission system (TETS) to include a rectification network and autonomous voltage regulation within the secondary coil, a hermetically sealed electronics package containing a miniaturized implementation of the existing redundant drive and control electronics with several power-input options, an implanted rechargeable lithium ion battery pack capable of providing up to 1 h of untethered operation, implantable electrical connectors that allow components to be connected after placement in the body or to be replaced if needed, and a radio telemetry subsystem to transmit diagnostic information and to permit remote adjustment of selected parameters.

Clinical characteristics and outcome of patients with invasive pneumococcal disease, Puy-de-Dôme, France, 1994-1998

A surveillance program for invasive pneumococcal disease was undertaken in Puyde-Dĵme, an administrative district of the region Auvergne in France, from 1 January 1994 to 31 December 1998. A total of 214 cases were identified. The annual incidence of invasive pneumococcal disease increased (P=0.04) from 5.5 in 1994 to 9.3 cases per 10(5) person-years in 1998. The highest incidences were for children <2 years of age (59.2 cases per 10(5) person-years) and for adults > or = 65 years (18 cases per 10(5) person-years). Clinical diagnoses, available in 200 patients, included acute pneumonia (62%), meningitis (10%), sepsis without focus (20%), and others (8%). The most frequent chronic medical conditions of the patients included smoking, alcoholism, cardiovascular and pulmonary diseases, and malignancies. Thirty-one percent of the isolates were nonsusceptible to penicillin. Penicillin resistance (MIC > or = 0.1 mg/l) was more frequent (P=0.02) in cancer patients. The overall case-fatality rate was 21.5%. Risk factors for death were age, sex, and underlying diseases of the patients, along with the severity of illness. These population-based findings should convince clinicians to offer pneumococcal vaccine to patients at high risk for invasive pneumococcal disease, thereby increasing vaccination coverage levels in France.

[Management of severe acute asthma in children in pediatric urgent and intensive care units]

Mortality in cases of severe asthma attacks in children is evaluated at 1%. During initial medical care, repeated evaluation of clinical and para-clinical severity criteria constitutes the main therapeutic guide. Emergency care treatment is based mainly on oxygen therapy, bronchodilatory therapy by discontinuous inhalation, and general corticotherapy. Intravenous theophylline treatment is controversial. The response after a few hours should allow a decision to be made [1] to follow up with outpatient treatment (rapid marked improvement), [2] to continue the hospital treatment (stabilization), or [3] to transfer to intensive care (worsening, exhaustion). In the intensive care unit, the treatment is based on continuous intravenous administration of beta 2 mimetics in addition to the above therapies. The objective is to avoid resorting to assisted ventilation. When this proves necessary, it must not be detrimental; controlled alveolar hypoventilation allows dynamic hyper-inflation linked to ventilation to be reduced. Prevention of relapse is indispensable. This requires hospitalization in a specialized care unit after discharge from intensive care.

Spinal sonography and magnetic resonance imaging in patients with repaired myelomeningocele: comparison of modalities

The goals of this study were to evaluate the feasibility of using ultrasonography of the spine in the follow-up evaluation of patients with repaired myelomeningocele at birth and to compare sonography with the accepted modality of magnetic resonance imaging. Over a period of 4 years we performed 165 sonographic studies in 101 patients; 107 sonographic studies had MR imaging results for comparison. We collected our data prospectively. The quality of the sonograms was good in 110 of 129 studies, acceptable in 17 of 129, and poor in two of 129. The sonographic examinations failed in 33 of 165 studies (20%). Concordant information was obtained between ultrasonography and magnetic resonance imaging in the following percentage of studies: level of the distal end of the cord in 82%, position of the cord in the canal in 59%, presence of hydromyelia in 63%, cord duplication in 96%, adhesions in 16%, intradural mass in 37%, cord measurements in 85%, and dural sac measurements in 83%. At the lumbosacral level, we saw no cord pulsation in 57% of the studies in patients with cord adhesions and in 20% of those without adhesions. At the lower thoracic level, we saw no pulsation in 35% of the studies in patients with cord adhesions and in 7% of those without adhesions. Postoperative studies of cord release surgery in eight patients showed varied findings. We conclude that in those patients who have a spinal defect or interlaminar space allowing proper visualization of the lumbosacral spinal canal, ultrasound can provide fairly similar information to that obtained with magnetic resonance imaging of that area with no need for sedation and at a reduced cost. Ultrasonography seems more sensitive than magnetic resonance imaging in the detection of cord adhesions, which is particularly relevant in the diagnosis of tethering.

Serum-dependent and cell cycle-dependent expression from a cytomegalovirus-based mammalian expression vector

Cytomegalovirus-based mammalian expression vectors are widely used to drive the expression of transfected genes in cultured cells. Immunofluorescent staining of the WT1 protein in 3T3 and 293 cell clones, stably transfected with a cyomegalovirus (CMV) expression vector carrying a cDNA coding for the tumour suppressor protein WT1, showed extreme cell to cell variation in the amount of recombinant protein expressed, indicative of cell cycle dependence. This was investigated further by Western blot and FACS analysis which showed that WT1 protein expression was highest in S phase and almost absent in G0/G1. Northern blot analysis of cell clones expressing sense or antisense WT1 cDNAs regulated by the CMV promoter/enhancer showed that RNA expression was also cell cycle-dependent. Western blotting of cells expressing a luciferase reporter gene driven by the CMV promoter/enhancer also showed apparent cell cycle-dependent expression. We further demonstrated that the expression of these gene constructs was serum responsive with a 10-fold increase in expression occurring 2 h after the addition of serum. These results show that the CMV promoter/enhancer system varied in its response to serum and the cell cycle state. Therefore, care must be taken when interpreting any phenotypic alterations (or lack of them) produced in cells transfected with CMV-based expression vectors.

Neuronal defects in genotyped dominant megacolon (Dom) mouse embryos, a model for Hirschsprung disease

Dominant megacolon (Dom) is one of four mutations in the mouse which can produce a phenotype similar to Hirschsprung disease in man. Here, we report that it is possible to take advantage of two microsatellite markers to genotype Dom embryos and to study enteric neuronal development in Dom embryos using whole-mount immunohistochemistry. Dom embryos present a variable defect in the ileo-caecal region, as do embryos of other murine models of Hirschsprung disease.

Tumorigenicity associated with chromosome 11p15 alterations in sv40-transformed human kidney-cells

Chromosome 11p15 has been suggested to be a potential site for a second Wilms' tumour gene (a childhood nephroblastoma). Human foetal kidney cells and normal kidney cells from Wilms' tumour patients were transformed with SV40 derivative vectors. As some of the cell lines progressed to tumorigenicity, we observed that chromosome 11p13, site of the WT1 suppressor gene, did not show any allelic loss. However, RFLP analysis showed that chromosome 11p15 was affected by allelic losses on different genes in some cell lines but not necessarily prior to the appearance of tumorigenicity. We also observed that the most aggressive cell Line (SVCU/NK), derived from the normal kidney cells of a Wilms' tumour patient, showed increased expression of c-Ha-ras proto-oncogene at later passage and in the tumour tissue extracted from nude mice. Finally we report a lack of tumour suppression activity of one cell line SVT1B6/NK, when fused with the tumorigenic G401 cell line (the latter has been used in tumour suppression experiments as a Wilms' tumour cell line before being identified as a Rhabdoid tumour cell line). These experiments are consistent with the existence of a suppressor gene at chromosome 11p15.

MR features of pachymeningitis presenting with sixth-nerve palsy secondary to sphenoid sinusitis

Pachymeningitis manifested by localized enhancing dural thickening adjacent to the clivus on MR images of two patients with sphenoid sinusitis and sixth-nerve palsy is presented. This is an unusual complication of sphenoid sinusitis. Prompt diagnosis and therapy may avoid significant intracranial complications.

Autoregulation of the human WT1 gene promoter

The human Wilms tumour suppressor gene, WT1, encodes a zinc-finger protein which can function as a transcriptional activator or suppressor. This study reports the analysis of the human WT1 gene promoter, and demonstrates that high levels of WT1 expression lead to autosuppression of the WT1 promoter. Deletion analyses of the promoter region implicate sequences 5' and 3' of the transcriptional start site as being crucial in WT1 autosuppression. Loss or alteration of this function of WT1 may be important in tumourigenesis.

Magnetic resonance abnormalities and cardiovascular disease in older adults. The Cardiovascular Health Study

BACKGROUND AND PURPOSE

Cerebral magnetic resonance imaging often detects abnormalities whose significance is unknown. The prevalence and correlates of findings such as ventricular enlargement, sulcal widening, and increased white matter signal intensity were examined in 303 men and women aged 65 to 95 years participating in a multicenter study of cardiovascular disease.

METHODS

Cerebral magnetic resonance imaging was performed and interpreted according to a standard protocol, and findings were correlated with measures of cardiovascular disease and its risk factors.

RESULTS

Measures of cerebral atrophy increased with age and were greater in men than in women (each P < .01). Ventricular enlargement and sulcal widening were associated with prior stroke, hypertension, diabetes, and white race (each P < .03). Extent of white matter hyperintensity was associated with age, prior stroke, hypertension, and use of diuretics (each P < .004). On multivariate analysis, age, male gender, white race, and prior stroke retained strong associations with increased ventricular and sulcal scores. After adjustment for age, prior stroke, and other risk factors, white matter hyperintensity was associated with atherosclerosis as measured by increased internal carotid artery thickness on ultrasound.

CONCLUSIONS

Cerebral atrophy and white matter hyperintensity are common in the elderly and are associated with age, prior stroke, and known cardiovascular risk factors. Though these findings have been suggested to represent normal aging, their wide variability and associations with cardiovascular disease argue against their inevitability with advancing age and support the need to identify modifiable risk factors for these abnormalities.

Environmental signals and neural crest cells

Cell lineage analysis in both the central and peripheral nervous system of vertebrates has revealed that many neural progenitor cells are multipotent. These observations have raised the general issue of when and how such multipotent progenitors generate their various differentiated progeny. The environment of these progenitors controls the cell lineage decisions in the neural crest. This review considers the roles of the environmental signals in the context of the development of several different neural crest-derived lineages.

Carcinomatous encephalitis (miliary metastases): lack of contrast enhancement

Carcinomatous encephalitis is a rare form of brain metastasis in which there is diffuse miliary spread of punctate tumor nodules in a perivascular distribution. In this case, these tiny tumor nodules were seen throughout the cortical and basal gangliar gray matter only on T2-weighted images. Contrast-enhanced CT and T1-weighted MR images did not demonstrate these tumor nodules.

Inactivation of the remaining allele of the WT1 gene in a Wilms' tumour from a WAGR patient

A candidate gene (WT1) has recently been described for the 11p13 tumour-suppressor gene involved in the development of Wilms' tumour. This gene encodes a zinc finger protein which can bind to a specific DNA sequence. We have found a 226 base deletion in the mRNA from a unilateral Wilms' tumour, which would cause a frameshift that completely deletes the zinc finger domain. The tumour developed in a patient suffering from the WAGR syndrome, who had a constitutional 11p13 deletion, and so the 226 base deletion represents the inactivation of the remaining WT1 allele in the tumour. This provides further direct evidence that loss of function of WT1 is an essential step in the development of Wilms' tumour.

Analysis of high PSA N-CAM expression during mammalian spinal cord and peripheral nervous system development

Using a monoclonal antibody that recognizes specifically a high polysialylated form of N-CAM (high PSA N-CAM), the temporal and spatial expression of this molecule was studied in developing spinal cord and neural crest derivatives of mouse truncal region. Temporal expression was analyzed on immunoblots of spinal cord and dorsal root ganglia (DRGs) extracts microdissected at different developmental stages. Analysis of the ratio of high PSA N-CAM to total N-CAM indicated that sialylation and desialylation are independently regulated from the expression of polypeptide chains of N-CAM. Motoneurons, dorsal root ganglia cells and commissural neurons present a homogeneous distribution of high PSA N-CAMs on both their cell bodies and their neurites. Sialylation of N-CAM can occur in neurons after their aggregation in peripheral ganglia as demonstrated for dorsal root ganglia at E12. Furthermore, peripheral ganglia express different levels of high PSA N-CAM. With in vitro models using mouse neural crest cells, we found that expression of high PSA N-CAM was restricted to cells presenting an early neuronal phenotype, suggesting a common regulation for the expression of high PSA N-CAM molecules, neurofilament proteins and sodium channels. Using perturbation experiments with endoneuraminidase, we confirmed that high PSA N-CAM molecules are involved in fasciculation and neuritic growth when neurons derived from neural crest grow on collagen substrata. However, we demonstrated that these two parameters do not appear to depend on high PSA N-CAM molecules when cells were grown on a fibronectin substratum, indicating the existence of a hierarchy among adhesion molecules.

Traumatic aneurysm of the superior cerebellar artery: case report and review of the literature

Less than 10% of the 250 reported cases of traumatic intracranial aneurysms have involved the posterior circulation. Traumatic aneurysms of the superior cerebellar artery are extremely rare, with only three cases previously reported. This is the first report of a traumatic superior cerebellar artery aneurysm in which the diagnosis was suggested by computed tomographic scan. The potential for a good outcome suggests the value of early angiography when the history and diagnostic imaging studies suggest the possibility of a traumatic aneurysm.

Molecular and cellular biology of Wilms' tumour

Wilms' tumour is an embryonal kidney tumour which exists in an hereditary and sporadic form. Apart from its obvious importance as a model for renal development and differentiation, the tumour has recently been exploited as an example of the action of tumour suppressor genes (or anti-oncogenes). The latter genes are characterised by a somatic loss of genetic information in tumour development, specifically from the short arm of human chromosome 11 in Wilms' tumour. To further study the developmental aspects of the tumour we have established in vitro cell cultures from tumour tissues, which, unlike the majority of Wilms' tumour cell lines, have been genotyped according to their chromosome 11 gene status and their antigen expression patterns, compared to the original normal kidney and tumour tissues. The cell cultures exist both as primary and secondary cultures, and their limited life span in culture has been extended by transfection of SV40 large T antigen. The mechanism of tumour suppression by the Wilms' locus has been explored by producing cell hybrids between the immortalised kidney cells, and an "indicator cell" (HeLa), whose chromosome 11 genotypes have been monitored in vivo and in vitro by restriction fragment length polymorphisms. Non-random patterns of inheritance of the mutant allele have also been investigated, both in tumour tissue and in syndromes, like the Beckwith-Wiedemann Syndrome, which pre-dispose to development of Wilms' tumour (and other embryonal tumours). It is also apparent that allele-specific methylation occurs in Wilms' tumour tissues, probably resulting in changes of gene expression patterns. Significant elevation of transcription of the N-myc oncogene was detected in the blastemal cells of the most malignant Wilms' tumours, whereas a marked decrease in the expression of HLA class I, at both RNA and protein levels was observed in the same cells. Wilm's tumour provides a clear illustration of the requirement for a combination of dominantly and recessively acting genes, in order to produce a malignant embryonal tumour.

Loss of chromosome 11p alleles in cultured cells derived from Wilms' tumours

Cell cultures have been produced from five Wilms' tumours. All cultures had a finite lifespan and a pattern of antigen expression which indicated that the cells were derived from the differentiated components of the tumours. No cells showed any of the expected characteristics of the putative Wilms' tumour stem cell. Nevertheless, in both cases where the original tumours showed a loss of heterozygosity at chromosome 11p alleles, the cultured cells also demonstrated a loss of heterozygosity. Thus these cell cultures definitely originated from Wilms' tumour tissue. The results demonstrate that cell cultures can be produced from the differentiated tissues present in Wilms' tumours and that these non-immortal cells show no 'transformed' phenotype, even though they possess the genetic changes present in the original tumour.

SV40 transfection of human kidney epithelial cells and stability of chromosome 11

Simian virus 40 (SV40) transformation has been used in a variety of mammalian cells and has been shown to extend their life span. We therefore decided to apply these results to normal kidney and tumoral cells derived from Wilms' patients. Wilms' tumour, a nephroblastoma which presents in early childhood, has been linked to deletions and rearrangements in chromosome 11. Analysis of gene structure in the 11p13 locus involved in the development of the tumour has been restricted by the very short life-span of the tumoral cells in vitro. We transfected normal kidney WT/NK, tumoral WT/T cells and human foetal kidney HFK cells with 2 SV40-derived plasmids SV3neo (pBR322-SV40-containing neomycin bacterial gene) and SVori- (pMK-origin mutated SV40). We isolated a high number of SV40-transfected cell lines. The efficiency of transfection appeared to be extremely low in WT/T cells compared with HFK and even WT/NK. The life span of the cell lines was increased in relation to their untransfected homologues. However, in all of the cell lines except 3, senescence occurred, after crisis step or not. We looked at different markers associated with SV40 transformation of mammalian cells and specifically with the presence of SV40 T antigen in the cells and its consequences: AIG, tumorigenicity, expression and insertion in genomic DNA of SV40 T antigen. Genetic studies involving karyotypic and restriction fragment length polymorphism (RFLP) analysis demonstrated that, despite a frequent pseudo-diploidy, the cell lines derived have conserved the 11p13 locus.

Expression of the N-myc oncogene in Wilms' tumour and related tissues

Tissue samples and cell cultures from Wilms' tumour matched histologically normal kidney samples and EBV transformed B cells from the same patients, were analysed to detect changes in the structure and expression of the N-myc oncogene. The levels of expression of HLA class I and hypoxanthine guanine phosphoribosyl transferase were also measured in the various RNA preparations. Related tissue samples, from sources including congenital mesoblastic nephroma, paediatric neuroblastoma and a number of foetal tissues were also tested. Northern blot analysis indicated that the levels of N-myc were higher in Wilms' tumour tissues (with no parallel increase in gene copy number) compared to all other sources of material including foetal kidney. Particularly high levels of expression were observed in a number of the Wilms' tumours, several of which produced metastases. In situ hybridization, using [35S]-labelled RNA probes, confirmed that the high levels of N-myc RNA were present in the blastemal elements in the Wilms' tumour. All the tissue cultures, and tissue samples from other sources, except foetal brain and neuroblastoma, contained uniformly low levels of N-myc RNA.

NAD and the synthesis of (ADP-ribose)n in a human cell strain (46BR) hypersensitive to the lethal effects of 3-aminobenzamide

The cell strain 46BR, derived from an immunodeficient individual, is hypersensitive to the lethal effects of DNA-damaging agents, and of 3-aminobenzamide (3AB), the latter being an inhibitor of the enzyme ADP-ribosyltransferase (ADPRT). This hypersensitivity is not found with the noninhibitory analogue, 3-aminobenzoate. The NAD content of 46BR cells is similar to that of fibroblasts from normal human donors, as is the decrease in NAD content following treatment with dimethylsulphate. Both the activity of ADP-ribosyltransferase and its inhibition by 3AB in permeabilized cells are similar in 46BR and in normal cell strains. High concentrations of 3AB interfere with purine metabolism in cultured cells. Again this effect is similar in 46BR and normal cells. Thus there is no apparent anomaly either in the activity of ADPRT or in the gross effects of 3AB in 46BR. The sensitivity to 3AB may be caused by a defect in a specific acceptor for the ADP-ribose synthesized by ADPRT, or in some as yet undiscovered action of the inhibitor.

Chromosomal aberrations induced by ethylene oxide in a human amniotic cell line in vitro

Ethylene oxide was found to be a potent inducer of chromatid-type aberrations in a human amniotic cell line. This induction was dose-dependent. At doses corresponding to about 9% survival, the number of chromatid exchanges was increased about 20 times, and the number of induced breaks increased 50 times, above that observed in the controls.

An appraisal of blood trauma and blood-prosthetic interface during left ventricular bypass in the calf and humans

Mechanical circulatory support was accomplished in 20 calves (mean, 140 days) and in 5 patients following operation for acquired heart disease (range, 1 hour to 8 days) employing a pneumatically actuated xenograft-valved assist pump interposed between the left ventricular apex and aorta. Following pump implantation in calves, hematocrit and platelets decreased transiently and returned to normal within 14 days. Plasma hemoglobin and erythrocyte mechanical fragility values were elevated for 48 hours. Platelet survival was slightly reduced, but erythrocyte survival values were similar to controls. In patients who received assist pumps, plasma hemoglobin and erythrocyte mechanical fragility were transiently elevated, but rapidly decreased to normal. Thrombocytopenia occurred only in the presence of bleeding and renal failure requiring hemodialysis. Pump flow of the left ventricular assist device was maintained above 2.0 L/min/m2 despite serious arrhythmias. Postmortem examination revealed no evidence of thromboemboli in the clinical patients although anticoagulant agents were not administered.

Advances in electrical assist devices

Marked improvements were realized in the development of electrically driven left ventricular assist systems. A volume reduction of 46%, a system weight reduction of 63%, and a factor of 2 improvement in overall efficiency (29%) were realized. The system, operating at a pressure of 120 mm Hg with a flow rate of approximately 7 L, requires only 7.5 W of input power. In addition, a unique brushless commutator was designed to replace standard brushes, thus increasing system life. A new polyurethane was synthesized for utilization in the TMS. This material has demonstrated high flex life in addition to being biocompatible. Further improvements in system weight and size, as well as efficiency, will be realized when flat plate pumps are mated to electric drivers.

Selection of materials for ventricular assist pump development and fabrication

A study was undertaken to select 2 of the most promising bladder materials from a list of 8 carefully chosen polymers. The polymers chosen for testing included a wide spectrum of urethanes, as well as a polyester resin and a millable polyolefin rubber. The following materials were studied: Adiprene LW-500, Avcothane 51, Biomer, Hexsyn, Hytrel 4055, Mobay 240313, Pellethane 2103-80 AE, and Tecoflex HR. The selection process was based on a test matrix which was divided into segmented steps, each a logical sequel from its predecessor, and each of increasing technical complexity. Hydrolytic stability, flexure endurance, fabricability, tissue compatibility, hemocompatibility and chronic tissue compatibility were evaluated, forming the basis for the acceptance/rejection criteria. As a result of this search, 2 biomaterials were identified as most suitable for use in conventionally flocked bladders; Biomer and Tecoflex HR. Both Biomer and Tecoflex HR bladders have demonstrated impressive results in circulatory analog loop endurance tests, with Tecoflex bladders surpassing 50 million flexes to date, and Biomer bladders (the longest running bladders) exceeding 150 million flexes. Tests are continuing.