The gene coding for interferon-gamma is linked to the D12S335 and D12S313 microsatellites and to the MDM2 gene

Interferon-gamma is a cytokine with multiple effects. It interferes with the replication of several viruses and plays a key role in the regulation of immune responses. Therefore, the gene coding for interferon-gamma could be implicated in the susceptibility of humans to several diseases. We have localized this gene close to the D12S335 and D12S313 microsatellites on both the physical and the genetic maps of the human genome. We also physically mapped this gene close to the MDM2 locus on chromosome band 12q15. Finally, we describe the organization of the Ifg, Myf-6, Mdm1, and Mdm2 loci on mouse chromosome 10, in a region syntenic to human chromosome band 12q15.

Theiler's virus infection of 129Sv mice that lack the interferon alpha/beta or interferon gamma receptors

The Daniels strain of Theiler's virus causes a persistent infection of the white matter of spinal cord of susceptible mice, with chronic inflammation and primary demyelination. Inbred 129Sv mice are resistant to this infection; they present with mild encephalomyelitis and clear the infection within a matter of days. A very different outcome was observed with inbred 129Sv mice whose receptors for interferon alpha/beta or interferon gamma had been inactivated by homologous recombination. The former presented severe encephalomyelitis with acute infection of neurons, particularly in brain and hippocampus, and extensive infection with necrosis of the choroid plexus. Most animals died of this acute disease. The latter, presented the same early encephalomyelitis as the control 129Sv mice. However, they remained persistently infected and developed a very severe late infection of the white matter with extensive primary demyelination. This late disease looked like an exacerbated form of the chronic demyelinating disease observed in susceptible inbred mice such as the SJL/J or FVB strains. Our results show that the two interferon systems play nonredundant roles in the resistance of the 129Sv mouse to the infection by Theiler's virus. They also lend support to the notion that the Ifg gene is involved in the resistance/susceptibility of inbred strains of mice to persistent infection by this picornavirus.

T lymphocyte repertoire in Theiler's virus encephalomyelitis: the nonspecific infiltration of the central nervous system of infected SJL/J mice is associated with a selective local T cell expansion

Theiler's virus causes, in the susceptible SJL/J mouse, a chronic demyelinating disease that resembles multiple sclerosis. Demyelination is at least in part immune mediated and coincides with the infiltration of the central nervous system by T lymphocytes. We analyzed the repertoire of the T cell receptor (TcR) beta-chain for each V beta-J beta combination, in spinal cord and spleen T cells of infected animals. All V beta families were detected in spinal cord as well as in spleen, as if the central nervous system were undiscriminantly invaded by T cells in the infected animals. Some T cells, defined by specific V beta-J beta combinations, were expanded in the spinal cord but not in the spleen, most probably because of an antigen-driven response. The TcR beta-chain repertoire of infiltrating T cells was the same at the onset of demyelination as when the disease was full-blown. These results provide the first description of the repertoire of the T cells which infiltrate the central nervous system during the course of this disease.

Isolation from human brain of six previously unreported cDNAs related to the reverse transcriptase of human endogenous retroviruses

cDNAs prepared from total RNA extracted from plaques of multiple sclerosis were amplified by the polymerase chain reaction. The 11-bp degenerate primers used were derived from conserved sequences of reverse transcriptase. Amplified cDNAs were fractionated according to size by electrophoresis in polyacrylamide gels under denaturing conditions. cDNAs of the proper size were cloned, grouped according to the sequence of their insert by differential hybridization, and sequenced. Six cDNAs were isolated and found to belong to new members of two groups of human endogenous retroviruses: the group related to ERV9 and that related to HERVK10 and HUMMTV. These sequences were expressed in all human organs tested, including normal white matter of brain. The approach described in this article is a powerful tool with which to isolate new members of the reverse transcriptase gene family.

FVB mice transgenic for the H-2Db gene become resistant to persistent infection by Theiler's virus

The DA strain of Theiler's virus causes a persistent infection of the white matter of the spinal cord with chronic inflammation and primary demyelination. Inbred strains of mice differ greatly in their susceptibility to this disease. It has been shown that both viral persistence and demyelination are controlled mainly by a gene located in the H-2D region. This raised the possibility that the H-2D gene itself controls viral persistence, which in turn determines demyelination. In the present work we introduced the H-2Db gene of resistant C57BL/6 mice into the genome of susceptible H-2q FVB mice and showed that the FVB mice become resistant to persistence of the infection and did not develop inflammatory lesions.

Mapping loci influencing the persistence of Theiler's virus in the murine central nervous system

Inbred strains of mice differ greatly in their susceptibility to the demyelinating disease caused by Theiler's Murine Encephalomyelitis Virus. In this murine disease, which is an animal model for the study of multiple sclerosis, demyelination depends on the persistent infection of the central nervous system. Previous studies identified a locus in the H-2D region of the major histocompatibility complex which controls susceptibility to the persistent infection, and also showed that other loci are involved. In order to identify these loci, we screened the genome of a set of backcross animals with a combination of polymorphic microsatellites and restriction enzymes sites. We now show that viral persistence is also controlled by a locus close to Ifg on chromosome 10 and possibly by a locus near Mbp on chromosome 18.

A new human brain cDNA molecule: assignment to chromosome 11q21-q23.1 and description of two polymorphisms studied by the polymerase chain reaction

A new human brain cDNA molecule was mapped by in situ hybridization to the 11q21-q23.1 region of the human genome, probably to the 11q22 band. An EcoRI restriction site and a (GT)n repeat element within the gene were shown to be polymorphic. Both polymorphisms were readily studied by the polymerase chain reaction. A two-allele polymorphism was described for the EcoRI restriction site, whereas four different alleles were detected for the second genetic marker. The observed heterozygosities were 37% and 42% for the former and the latter polymorphism, respectively. The combined heterozygosity index was estimated to be 0.56. These new genetic markers will be useful for linkage analysis of neurogenetic diseases that have been mapped to this chromosomal region.

Analysis of proteolipid protein and P0 transcripts in mice infected with Theiler's virus

Inbred strains of mice vary in their susceptibility to the chronic inflammatory and demyelinating disease caused by Theiler's virus. The severity of this disease depends on the extent of demyelination but also on the occurrence of remyelination. We studied the extent of demyelination and remyelination in mice with different genetic backgrounds. To estimate the extent of demyelination, we analyzed the abundance of proteolipid protein (PLP) transcripts in the spinal cord 45 days after inoculation. RNA transcripts were quantitated at the single cell level using in situ hybridization. We observed a correlation between the reduction of PLP mRNA and the extent of inflammation in the SJL/J, C3H, F1 SJL x C3H and C3H.Q strains. Remyelination by Schwann cells was estimated by the detection of P0 mRNA and was observed in C3H mice only. It is likely that intense inflammation in highly susceptible strains prevents the migration of Schwann cells into the central nervous system (CNS).

The interaction of two groups of murine genes determines the persistence of Theiler's virus in the central nervous system

Theiler's murine encephalomyelitis virus is responsible for a chronic inflammatory demyelinating disease of the central nervous system of the mouse. The disease is associated with persistent viral infection of the spinal cord. Some strains of mice are susceptible to viral infection, and other strains are resistant. The effect of the genetic background of the host on viral persistence has not been thoroughly investigated. We studied the amount of viral RNA in the spinal cords of 17 inbred strains of mice and their F1 crosses with the SJL/J strain and observed a large degree of variability among strains. The pattern of viral persistence among mouse strains could be explained by the interaction of two loci. One locus is localized in the H-2D region of the major histocompatibility complex, whereas the other locus is outside this complex and is not linked to the Tcrb locus on chromosome 6.

Analysis of retroviral sequences in the spinal form of multiple sclerosis

The polymerase chain reaction was used, in a blind study, to look for retroviral sequences in DNA extracted from the peripheral blood mononuclear cells of 11 patients with the spinal form of multiple sclerosis (MS). Control subjects consisted of 7 patients with other neurological diseases and 5 healthy blood donors. Three sets of oligonucleotides were used. They could detect all known human oncoretroviruses, lentiviruses, or spumaretroviruses. The primers recognized conserved sequences in the long terminal repeats of the proviral DNA. Control experiments showed that the primers crossreacted within the human immunodeficiency virus or human T-cell lymphotropic virus group and that they provided the expected level of sensitivity. Therefore the assay could have detected not only known human retroviruses but also new related members. In spite of this, no retroviral sequences were detected in either the MS or the control specimen.

Isolation of a specific cellular mRNA by subtractive hybridization in Theiler's virus persistent infection

Viruses change the mRNA repertoire of the tissues they infect. They add viral mRNAs and they specifically alter the expression of some host genes. These events can play important parts in pathogenesis. In principle, it should be possible to isolate viral mRNAs and to identify changes in host gene expression using subtractive hybridization. We tested this approach in the persistent infection of mouse central nervous system by Theiler's virus. A cDNA library was constructed with poly A+ RNA from infected mouse spinal cords. The library was screened with a subtracted probe. We identified one mitochondrial gene, coding for subunit 1 of cytochrome oxidase, which is overexpressed in infected tissues whereas another mitochondrial gene, URF 2, is not. Subtractive hybridization should prove to be invaluable in studying the pathogenesis of chronic human central nervous system diseases of unknown etiology.

[Quantitative study of the pulmonary uptake of thallium 201 during exercise and redistribution in the coronary patient]

In some patients with coronary disease hyperactivity of the lungs is commonly observed when the myocardial scintigraphic images are recorded during exercise. Pulmonary activity of radionuclide tracers has been reported in the literature and quantified in different ways. The present study contributes to this quantification by suggesting a new index: the pulmonary activity to cardiac activity percentages ratio during exercise and blood redistribution. The value of the new index has been evaluated comparatively in 11 subjects with normal coronary arteries (0.76 +/- 0.09) and in 39 patients with angiographically proven coronary disease (0.92 +/- 0.10; p less than 0.001). Remarkably, this index hardly varies in normal subjects and therefore is a highly specific aid to diagnosis. In coronary patients, multivariate analysis has shown that it correlates in decreasing order of intensity with: (1) a left ventricular end-diastolic pressure of 14 mmHg or more; (2) a moderate rise in heart rate at exercise; (3) a moderate heart work; (4) an ST depression of 2 mm or more; (5) a multilocular myocardial ischaemia at scintigraphy. Our index did not prove capable of discriminating between one-, two- or three- vessel diseases. In view of the data obtained in this study and those found in the literature, this index should be regarded as a reliable marker of left ventricular dysfunction during stress. Being relatively inexpensive and easy to obtain, it complements myocardial scintigraphy and may be useful in clinical practice.

Diagnostic and prognostic criteria of chronic left ventricular failure obtained during exercise-201Tl imaging

Lung thallium fixation was studied during stress effort and redistribution in 39 patients with proven coronary artery disease (CAD) and in 11 control patients. The quantitative indices (Lung Stress Index (LSI), Lung Redistribution Index (LRI), and their ratio (LSI/LRI] were tested. The last one best correlated with left ventricular end diastolic pressure elevation and positive stress test. Detection of left ventricular failure was possible (sensitivity 80%, specificity 95%) using LSI and LSI/LRI. These indices could detect left ventricular failure in high-risk patients.

Orientation and vertical fluctuations of spin-labeled analogues of cholesterol and androstanol in phospholipid bilayers

We have used ESR and NMR linewidth broadening by spin-labels to determine the overall orientation of spin-labeled analogues of cholesterol and androstanol in egg lecithin bilayers. While the cholesterol analogues were found to have a single orientation in each monolayer, with the acyl chain pointing towards the center of the bilayer, the androstanol analogue appeared, at least in sonicated vesicles, to experience two opposite orientations in the same monolayer, very likely with a rapid reorientation. The possibility of rapid vertical fluctuations of the sterol molecules within the phospholipid bilayer is also discussed.

Asymmetric lateral mobility of phospholipids in the human erythrocyte membrane

The fluorescent phospholipid 1-acyl-2-[12-(7-nitrobenz-2-oxa-1,3-diazol-4- yl)aminododecanoyl]phosphatidylcholine (NBD-phosphatidylcholine) and the corresponding aminophospholipid derivatives (NBD-phosphatidylethanolamine and NBD-phosphatidylserine) were introduced in the human erythrocyte membrane by a nonspecific phospholipid exchange protein purified from corn. The lateral mobility of the fluorescent phospholipids was measured by using an extension of the classical photobleaching recovery technique that takes advantage of a modulated fringe pattern and provides a high sensitivity. In intact erythrocytes and in ghosts resealed in the presence of ATP, the fluorescence-contrast curves after photobleaching decayed biexponentially corresponding to two lateral diffusion constants. With NBD-phosphatidylcholine, the majority of the signal corresponded to a "slow" component (1.08 X 10(-9) cm2/sec at 20 degrees C), whereas with the amino derivatives the majority of the signal corresponded to a "fast" component (5.14 X 10(-9) cm2/sec at 20 degrees C). If the ghosts were resealed without ATP, the fast component of the aminophospholipids disappeared. We interpret these results as follows: (i) Provided the cells or the ghosts contain ATP, the three fluorescent phospholipids distribute spontaneously between inner and outer leaflets as endogenous phospholipids, namely NBD-phosphatidylcholine is located in the outer leaflet, while both aminophospholipids are preferentially located in the inner leaflet. (ii) The viscosity of the inner leaflet of human erythrocyte membranes is lower than that of the outer leaflet.

Blood pressure, coffee, tea and tobacco consumption: an epidemiological study in Algiers

The connections and possible interactions between coffee consumption, tobacco consumption, blood pressure (BP), age, and body mass index (BMI) were analysed in a cross-sectional epidemiologic study of 1098 men and 393 women of the Algiers district. Systolic blood pressure (SBP) was negatively and significatively correlated with cigarette smoking. Diastolic blood pressure (DBP) was positively and significantly associated with coffee consumption (P less than 0.001) and negatively and significantly with cigarette consumption (P less than 0.001). These associations remained significant after multivariate analysis including sex, age, BMI, physical exertion at work, athletic activity, rural versus urban residency, tobacco, tea and coffee consumption. Coffee consumption and cigarette smoking were positively associated (P less than 0.001). In the subgroup of men, the association between coffee consumption and DBP was significant only after adjustment for cigarette smoking. In the subgroup of women, containing a low percentage of smokers, this association was significant without such adjustment. This finding suggests that cigarette consumption might partly mask the association between coffee consumption and BP. The contradictory interactions observed between BP, cigarette consumption and coffee consumption might help to explain the conflicting reports concerning the association between coffee consumption and ischemic heart disease.