Mammalian postmitotic nuclei reenter the cell cycle after serum stimulation in newt/mouse hybrid myotubes

Cell cycle reentry and dedifferentiation of postmitotic cells are important aspects of the ability of an adult newt and other urodele amphibians to regenerate various tissues and appendages [1]. In contrast to their mammalian counterparts, newt A1 myotubes are able to reenter S phase after serum stimulation of a pathway leading to phosphorylation of the retinoblastoma protein, pRb [2]. The activity in serum is not due to mitogenic growth factors but is generated indirectly by the activation of thrombin and subsequent proteolysis [3]. In this paper we describe the formation of interspecies hybrid (heterokaryon) myotubes by the fusion of mouse C2C12 [4] and newt A1 [5, 6] myogenic cells. The C2C12 nuclei reenter the cell cycle upon serum stimulation of the hybrids, while C2C12 homokaryon myotubes remain arrested under these conditions. These findings indicate that the postmitotic arrest of the mouse nuclei is undermined by the pathway activated in the newt cytoplasm. The hybrid myotubes provide a new model for the manipulation of the postmitotic arrest in both mammalian and newt differentiated cells.

Meropenem versus ceftazidime as empirical monotherapy in febrile neutropenia of paediatric patients with cancer

This trial assessed the efficacy and safety of meropenem versus ceftazidime as empirical monotherapy for febrile neutropenia in paediatric cancer patients. In a prospective randomized study, 172 evaluable febrile episodes in the meropenem arm and 170 episodes in the ceftazidime arm were analysed for the clinical and microbiological response dependent on the kind of infection. About half the episodes were classified as fever of unknown origin (FUO) and the remainder as microbiologically or clinically documented infections. The most frequently documented infections in both arms were bacteraemias (22.1 versus 26.5%), predominantly caused by Gram-positive organisms (57.9 versus 71.1%). The success rate of the initial monotherapy differed significantly between the two arms and was 55.8% in the meropenem and 40.0% in the ceftazidime arm (P = 0.003). In addition, a significantly longer duration of fever and of antimicrobial therapy was observed in the ceftazidime arm than in the meropenem arm (median 5 versus 4 days, P = 0.022, and 7 versus 6 days, P = 0.009, respectively). With respect to the kind of infection, differences between the two arms were significant only in episodes classified as FUO but not in documented infections. In both arms, side effects were minimal. Despite the greater response rate for meropenem in FUO, the fact that ceftazidime has been proven to be as effective as meropenem in documented infections in the present study suggests that both drugs are useful as empirical monotherapy in febrile paediatric cancer patients.

Neighbourhood renewal and health: evidence from a local case study

This article presents findings from a before-and-after study of the effects of neighbourhood renewal on residents' health. Survey data were analysed using multivariate logistic regression. Before the renewal programme, damp and draughts had significant independent effects on respiratory health problems. Draughts and perceived community safety were associated with mental health problems. Children's mental health was associated with parental mental health. Following the renewal work, improvements occurred in both adults' and children's mental health, and smoking declined sharply. Respiratory health did not improve and there was no change in use of health services. Neighbourhood renewal in deprived areas can have an important role in improving community health.

Association studies between haemochromatosis gene mutations and the risk of cardiovascular diseases

BACKGROUND

Haemochromatosis is a common genetic disorder, inherited as an autosomal recessive trait that results in a progressive accumulation of iron in most tissues of the body. Positive association studies have been recently published between cardiovascular diseases and heterozygosity for the major mutation C282Y in the haemochromatosis gene HFE.

METHODS

In the present work, we have determined the HFE genotypes for C282Y and H63D in subjects from two case-control studies: the ECTIM and GENIC studies, designed to identify genetic variants associated with myocardial and brain infarction, respectively. In addition, we tested whether HFE mutations were associated with the degree of arteriosclerosis assessed non-invasively by Doppler ultrasonography on the carotid and femoral arteries, in a group of apparently healthy individuals (the AXA Study).

RESULTS

The prevalence of 282Y, and 63D allele carriers, did not differ between cases and controls in the ECTIM and in the GENIC studies, while 63D but not 282Y carriers were more numerous among subjects with atherosclerotic plaques in the AXA Study.

CONCLUSIONS

These three studies do not provide consistent evidence supporting the hypothesis that HFE mutations are associated with an increased risk of cardiovascular disease and with the development of arteriosclerosis.

Molecular analysis of MVK mutations and enzymatic activity in hyper-IgD and periodic fever syndrome

Hyperimmunoglobulinaemia D and periodic fever syndrome (HIDS) is an autosomal recessive inflammatory disorder characterised by recurrent episode of fever associated with lymphadenopathy, abdominal distress, joint involvement and skin lesions. We recently demonstrated that mutations in the mevalonate kinase gene (MVK) are associated with HIDS. Direct DNA sequencing was done to screen the entire coding region of MVK in 25 unrelated patients with HIDS. Mutations were detected in the coding region of the gene including 11 missense mutations, one deletion, the absence of expression of one allele, as well as three novel polymorphisms. Seven of these mutations are novel. The large majority of the patients were compound heterozygotes for two mutations. Of these, V377I (G-->A) is the most common mutation occurring in 20 unrelated patients and was found to be associated with I268T in six patients. Mutations were associated with a decrease of mevalonate kinase (MK) (ATP:mevalonate 5-phosphotransferase, EC 2.7.I.36) enzymatic activity but not as profound as in mevalonic aciduria, a syndrome also caused by a deficient activity of MK. In HIDS the mutations are located all along the protein which is different from mevalonic aciduria where MK mutations are mainly clustered to a same region of the protein. On the basis of this study, we propose that the diagnostic screen of MVK in HIDS should be first directed on V377I and I268T mutations. Three patients are also described to illustrate the genotypic and phenotypic overlap with mevalonic aciduria.

Marital status and cardiovascular risk in French and Swedish automotive industry workers--cross sectional results from the Renault-Volvo Coeur study

OBJECTIVES

To compare the coronary risk profiles in a sample of the French and Swedish automotive industry employees who were married/cohabitant, divorced or single (never married).

DESIGN

A cross-sectional study comparison from biological and questionnaire data between the French and Swedish samples.

SETTING

Occupational health departments at Renault (employees from the north-west of France) and Volvo (employees from the south-west of Sweden).

SUBJECTS

Two random samples of males aged between 45 and 50 years were examined in 1993, from Renault 1000, and from Volvo 1000.

MAIN OUTCOME MEASURES

Biological data including cholesterol, blood pressure as well as the Framingham risk index. Self reported information regarding marital status, smoking, exercise, alcohol habits, and work stress assessed by the Karasek method, private social support indices, and type A behaviour according to the Bortner scale.

RESULTS

More employees were married/cohabitant and fewer divorced or single at Renault. Apart from waist/hip ratio being marginally lower in Swedish single men, compared with married and divorced, no significant difference in biological cardiac risk factors (total cholesterol, blood pressure or Framingham risk index) was seen between the subgroups from any of the two countries. Compared with married/cohabitant men, it was shown that in men living alone smoking was more prevalent at Renault and Volvo. These men also showed less type A behaviour, a lower work control and a lower work support and fewer close friends. Alcohol consumption was reported in smaller amounts for Volvo employees living alone compared with married or divorced employees. Married/cohabitant and divorced staff showed similar values regarding all measured variables when compared within each country.

CONCLUSIONS

Employees living alone in both France (Renault) and Sweden (Volvo) automotive companies seem to have increased nontraditional cardiac risk factors pertaining to life style and social network compared with married or divorced men. These results, in combination with the finding that more Volvo than Renault employees were living alone, suggest a higher risk for coronary heart disease amongst Volvo employees. This hypothesis will be evaluated in the 5 and 10 years follow up study.

Support for ethical dilemmas in individual cases: experiences from the Neu-Mariahilf Hospital in Göettingen

Prompted by a recommendation of the two Christian hospital associations in Germany, the Neu-Mariahilf Hospital in Göttingen set up a health ethics committee in autumn 1998. It is the committee's task to give support to staff members, patients and their relatives in individual cases where ethical dilemmas arise. The following article describes the committee's work by means of three cases.

Confirmation of the retinopetal/centrifugal nature of the tyrosine hydroxylase-immunoreactive fibers of the retina and optic nerve in the weaver mouse

The number of tyrosine hydroxylase-immunoreactive fibers in the nerve fiber layer is increased in the retina of the weaver compared to control mice (Dev. Brain Res. 121 (2000) 113). To confirm the retinopetal/centrifugal nature of these fibers, a newly devised whole-mounted optic nerve technique allowed us to determine, during development, their first appearance within the optic nerve (post-natal day 12) compared to retina (post-natal day 13). One such fiber was also observed looping in the retina of a monkey fetus.

Timing of leukocyte filtration during cardiopulmonary bypass

The effects of leukocyte filtration on the outcome of cardiac surgery with cardiopulmonary bypass (CPB) have been shown by numerous investigators. In the majority of cases a leukocyte filter is placed in the arterial line instead of a standard arterial line filter and used throughout CPB. However, protocols to optimize onset and duration of leukocyte filtration have not been sufficiently evaluated to date. In this paper, current efforts to improve such protocols are demonstrated and discussed. These efforts are based on studies of leukocyte pathogenicity during cardiac surgery. A first study (double-blind randomized) was performed in routine coronary artery bypass graft (CABG) patients to evaluate whether short-term leukocyte filtration during reperfusion by release of the aortic crossclamp would reduce reperfusion-associated myocardial damage. Further data compare the efficacy of three different filtration concepts to reduce CPB- and/or reperfusion-associated leukocyte pathogenicity. Clinical endpoints, standard laboratory variables and functional in vitro assays are provided and discussed.

Dag-1 carcinoma cell in studying the mechanisms of progression and therapeutic resistance in bladder cancer

OBJECTIVE

We describe a new human bladder carcinoma cell line (DAG-1) established from a resected bladder cancer fragment and maintained in culture for more than 5 years and over 300 passages.

METHODS AND RESULTS

Immunological, biochemical and molecular analysis showed that the DAG-1 cells (62 chromosomes) express the cytokeratines 8, 13, 18 and 20 that confirm their epithelial origin as well as numerous cytokine and cytokine receptor mRNAs. They secrete tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA), plasminogen activator inhibitors (PAI-1 and PAI-2), and express u-PA receptors (u-PAR/CD87) at their surface. DAG-1 cells are resistant to TNFalpha- and IFNgamma-induced apoptosis, two cytokines secreted in the urine of Calmette-Guérin bacillus-treated patients and involved in the tumor regression.

CONCLUSION

The DAG-1 cell line is a useful tool, both in vitro and in vivo, to study the progression of bladder tumors and their mechanisms of resistance to immunotherapy in relation with PAI-2 and antioxidant enzymes.

Prevalence and conditions of selection of E44D/A and V118I human immunodeficiency virus type 1 reverse transcriptase mutations in clinical practice

Recently, it has been shown that a new mutational pattern (the E44D/A and/or V118I mutation) confers moderate phenotypic lamivudine resistance in the absence of the M184V mutation. The E44D/A and/or the V118I mutation does not exist in drug-naive patients, and the prevalence increases with the number of treatment regimens and lamivudine experience. The mutations can preexist in nucleoside-experienced but lamivudine-naive patients. They are always associated with zidovudine resistance-associated mutations, even in the absence of M184V. These mutations are more stable than the M184V substitution during antiretroviral treatment interruptions.

A new DNA polymorphism in the 5' untranslated region of the human SREBP-1a is related to development of atherosclerosis in high cardiovascular risk population

Sterol-regulatory element binding proteins (SREBPs) are ubiquitous transcription factors that regulate the genes encoding key proteins in the control of cholesterol homeostasis. We looked for mutations or polymorphisms within the sequences of the SREBP-1a gene critical for the synthesis and/or activity of the protein in 204 asymptomatic men. A single G deletion at base pair -36 of the translation initiation site (designated G-) was found using single-strand conformation polymorphism (SSCP), in addition to three rare variants. This new marker was then assessed for its influence on the lipid parameters of 812 men at high cardiovascular risk, and on the presence of echographic atherosclerotic plaque in their peripheral arteries. The allelic frequency of the -36delG polymorphism was 0.58. At least one plaque was found in the carotid in 24% of subjects, in the femoral arteries of 48%, and in the aorta of 25%. There were significant associations between the -36delG polymorphism and mean total cholesterol (p=0.02) and LDL-cholesterol (P=0.02). There was a graded relationship between the G- allele and the presence of carotid plaque (r=0.084, P=0.02). In addition, there was a statistically significant interaction between the -36delG genotype and the apoE phenotype for plasma LDL-cholesterol (P=0.04) and apoB (P=0.05), suggesting a gene-gene interaction. Stepwise multiple regression analysis for lipid traits, risk factors, and apoE phenotype showed an independent association between carotid plaque and the -36delG polymorphism (beta=0.311, P=0.03). Thus, we have identified a new polymorphism in the 5' untranslated region of the SREBP-1a gene, and demonstrated its association with an atherogenic lipid profile and echographic plaques.

Effect of hypertension on viscoelasticity of large arteries in humans

Two traditional methodologic approaches, the analysis of the arterial pressure waveform in the time domain and the measurement of pulse wave velocity along the arterial tree, have been extensively used to determine the distensibility of large arteries in humans. They have shown that large artery walls are stiffened in the presence of hypertension. However, several methodologic limitations, especially the incapability of these methods to take into account the physiologic pressure-dependence of arterial distensibility, have led to the development of new approaches for characterizing more in depth the elastic and viscous properties of large arteries. The noninvasive recording of instantaneous pressure and diameter waveforms in superficial arteries (carotid or femoral) by means of tonometry and ultrasonography allows, via appropriate model of the arterial wall, determination of the pure elastic properties as well as the wall viscosity of the vessel. Using case (hypertensive)-control (normotensive) studies it has been found that elastic alteration (stiffening) was preferential in the femoral artery rather than in the carotid artery and that viscous alteration (increased wall viscosity) was relatively uniform in both arteries. This topographic dissociation between elastic and viscous responses of the arterial wall to hypertension suggests that the elastic alteration might be a local phenomena dependent on the singularities of the arterial system, whereas abnormal wall viscosity may reflect a more general influence of hypertension on large artery smooth muscle, the likely determinant factor of viscosity. Therefore, the elastic and viscous components of the arterial walls should be considered independently when assessing the development of hypertensive vascular change and its response to antihypertensive treatment.

[From gene to disease; tumor necrosis factor receptor and a syndrome of familial periodic fever]

Familial Hibernian fever (FHF) is a rare hereditary syndrome that causes periodic attacks of fever and inflammation. It is an autosomal dominantly inherited disorder. The gene involved in FHF encodes for a receptor for tumour necrosis factor (TNFR1). These mutations are thought to result in impaired shedding of the receptor from the cell membrane, leading to deficient curtailing of the inflammatory reaction. The acronym TRAPS (TNF-receptor associated periodic syndrome) has been proposed as a more accurate name.

Synthesis, characterization, and structural and theoretical analysis of Gd4B3C4: a novel rare earth metal borocarbide containing two different boron-carbon arrangements

The synthesis by arc-melting techniques, the single-crystal X-ray structure, and the theoretical analysis of Gd4B3C4 are reported. It crystallizes in the triclinic space group P1 with a = 3.637(2) A, b = 3.674(2) A, c = 11.859(5) A, alpha = 93.34(5) degrees, beta = 96.77(5) degrees, gamma = 90.24(5) degrees, and Z = 1. In this structure, the boron and carbon atoms form two different types of nonmetal arrangements: 1-D (BC)infinity branched chains and finite (0-D) linear CBC "molecular" units. Gd4B3C4 is the first characterized member of the rare earth metal borocarbide series in which both 1-D and "molecular" 0-D nonmetal atom systems coexist. From the structural and theoretical analysis, the following formal charge distribution can be proposed within the ionic limit: (Gd3+)4(BC2(5-)(BC3-)2.e-. Tight-binding calculations suggest that the excess electron in the ionic limit is mainly localized on the Gd atoms (at the bottom of the 5d band), while LAPW calculations favor its localization on the (BC)infinity chain. The bonding within this compound is fully analyzed and compared to other members of the rare earth metal borocarbide series.