Targeting the red nucleus for cerebellar tremor.

Deep brain stimulation of the thalamus (and especially the ventral intermediate nucleus) does not significantly improve a drug-resistant, disabling cerebellar tremor. The dentato-rubro-olivary tract (Guillain-Mollaret triangle, including the red nucleus) is a subcortical loop that is critically involved in tremor genesis. We report the case of a 48-year-old female patient presenting with generalized cerebellar tremor caused by alcohol-related cerebellar degeneration. Resistance to pharmacological treatment and the severity of the symptoms prompted us to investigate the effects of bilateral deep brain stimulation of the red nucleus. Intra-operative microrecordings of the red nucleus revealed intense, irregular, tonic background activity but no rhythmic components that were synchronous with upper limb tremor. The postural component of the cerebellar tremor disappeared during insertion of the macro-electrodes and for a few minutes after stimulation, with no changes in the intentional (kinetic) component. Stimulation per se did not reduce postural or intentional tremor and was associated with dysautonomic symptoms (the voltage threshold for which was inversed related to the stimulation frequency). Our observations suggest that the red nucleus is (1) an important centre for the genesis of cerebellar tremor and thus (2) a possible target for drug-refractory tremor. Future research must determine how neuromodulation of the red nucleus can best be implemented in patients with cerebellar degeneration.

Resveratrol protects neurons from cannulae implantation injury: implications for deep brain stimulation.

Brain-implantable electrodes such as those used in deep brain stimulation (DBS) have a promising future in end-stage Parkinson's disease therapy. However, there is considerable injury when electrodes penetrate brain tissue. For instance, broken blood vessels and glial scar formation may impede continual DBS or electrical recording from specific neurons. To begin addressing this key safety issue, we tested the therapeutic potential of resveratrol in reducing brain trauma caused by DBS-like surgery. Microinfusion of resveratrol (10 µM) directly applied to the sub-thalamic nucleus (STN) of the rat brain significantly minimized the formation of astrocytic gliosis in response to a 27-G precision-glide cannula implant. The therapeutic effects of resveratrol extended to the "kill zone", a boundary zone of about 100 µm comprising the cannula implant and surrounding neurons. We also found that resveratrol not only provided almost complete protection from mechanical injury to the brain, but that it also prevented undesirable motor deficits often seen in animals with lesions to the STN. Lastly, continuous infusion of resveratrol over a 4-week period led to the inhibition of pro-apoptotic, neurodegenerative and cell division cycle genes that may be associated with a reduction in astrocytic gliosis and glial scar formation within the STN. Taken together, these data suggest that application of resveratrol to the brain is an effective adjunct surgical procedure for minimizing acute neuronal injury when electrodes are implanted directly into the STN.

[Comunities of knowledge. Schools and colleges in Paris in the XIIIth century]. / Communautés de savoirs. Ecoles et collèges a Paris au xIIIe siècle.

The social and institutional history of the university of Paris still frequently remains detached from the study of the intellectual dynamics which were produced in its midst. The concept of "communities of knowledge" allows us to fill this gap by narrowly associating the history of knowledge to its concrete conditions of production and teaching. This model permits us to give attention to the maintenance, in the midst of the Parisian university of diverse "schools" endowed with orientations and specific programmes of research. The appearance of colleges can equally be situated in this perspective, which permits us to better grasp the interaction between the political and intellectual stakes which lay stress on the history of the university in the XIIIth century. Finally, it neveals the image of an institution more fragmented than unified.

[Clinical guidelines for the screening and the diagnosis of autism and pervasive developmental disorders]. / Recommandations pour la pratique clinique du dépistage et du diagnostic de l'autisme et des troubles envahissants du développement.

UNLABELLED: Autism is the best defined category among PDD. Its high prevalence, its onset in very young children and its persistence in adulthood arise many questions about early screening and early diagnosis. The aim of the study was to identify professional best practices about screening and diagnosis of autism in order to propose clinical guidelines and actions for the future. Scientific experts and parents take part to this procedure. Literature and previous guidelines were analyzed, experts in various fields were interviewed, a national study about the medical practices of the diagnosis of autism was made and questionnaires were send to 1600 psychiatrists and pediatricians. Guidelines built around 2 levels were proposed about screening and diagnosis. CONCLUSION: Diagnosis needs a multidisciplinary approach, validated instruments and more communication between professionals and parents. Finally one of the more important aims of the diagnosis of autism is to facilitate intervention program.

Photocrosslinking in ruthenium-labelled duplex oligonucleotides.

The formation of a photoadduct between a [Ru(1,4,5,8-tetraazaphenanthrene)(2)4,7-diphenylphenanthroline](2+) complex chemically attached to a synthetic oligonucleotide, and a guanine moiety in a complementary targeted single-stranded DNA molecule was studied for ten 17-mer duplexes by denaturing gel electrophoresis. This photoadduct formation leads to photocrosslinking of the two strands. The percentage quenching of luminescence of the complex by electron transfer was compared to the resulting yield of photocrosslinked product. This yield does not only depend on the ionisation potential of the guanine bases, which are electron donors, but also on other factors, such as the position of the guanine bases as compared to the site of attachment of the complex. The photocrosslinking yield is higher when the guanine moieties are towards the 3' end on the complementary strand as compared to the tethering site. Computer modelling results are in agreement with this preference for the 3' side for the photoreaction. Interestingly, the photocrosslink is not alkali labile. Moreover, a type III exonuclease enzyme is blocked at the position of photocrosslinking.

Luminescence quenching of Ru-labeled oligonucleotides by targeted complementary strands.

The yield of hole injection into guanines of different oligonucleotide duplexes by a photooxidizing tethered Ru(II) complex is examined by measuring the luminescence quenching of the excited complex. This yield is investigated as a function of the anchoring site of the complex (on a thymine nucleobase in the middle of the sequence or on the 5' terminal phosphate) and the number and position of the guanine bases as compared with the site of attachment of the Ru(II) compound. In contrast to other studies, the tethered complex, [Ru(tap)(2)(dip)](2+), is a non-intercalating compound and has been shown previously to produce an irreversible photocrosslinking between the two strands as the ultimate step of hole injection. The study of luminescence quenching of the anchored complex by emission intensity and lifetime measurements for the different duplexes indicates that a direct contact between the complex and the guanine nucleobase is needed for the electron transfer to take place. Moreover, for none of the sequences a clear contribution of a static quenching is evidenced independently of the two types of attachment of the [Ru(tap)(2)(dip)](2+) complex to the oligonucleotide. A comparison of the fastest hole-injection process by electron transfer to the excited anchored [Ru(tap)(2)(dip)](2+), with the rate of the photo-electron transfer between the same complex free in solution and guanosine-5'-monophosphate, indicates that the hole injection by the anchored complex is slower by a factor of 10 at least. A bad overlap between donor and acceptor orbitals is probably the cause of this slow rate, which could be attributed to some steric hindrance induced by the complex linker.

Translesional synthesis on DNA templates containing the 2'-deoxyribonolactone lesion.

A site-specifically modified oligonucleotide containing a single 2'-deoxyribonolactone lesion was used as a template for primer extension reactions catalyzed by M-MuLV reverse transcriptase (RT) and by the Klenow fragments of Escherichia coli DNA polymerase proficient (KF exo(+)) or deficient (KF exo(-)) in exonuclease activity. Analysis of the extension products in the presence of the four dNTPs or of a single dNTP showed that the M-MuLV RT was completely blocked and did not incorporate any dNMP opposite 2'-deoxyribonolactone. KF exo(-) preferentially incorporated nucleotides opposite the lesion following the frequency order dAMP > dGMP >> dTMP approximately dCMP and thus appeared to obey the 'A rule' for preferential incorporation as has been shown previously for the 2'-deoxyribose abasic site. In the sequence context examined, the primer extension by KF exo(-) appeared to be less efficient when dAMP was positioned opposite the lesion as compared with dTMP or dGMP. These two nucleotides promoted a more efficient polymerization accompanied by nucleotide deletion through misalignment incorporations. We therefore predict that the sequence context may strongly influence the translesional synthesis by KF exo(-) and thus the miscoding and mutational potential of the 2'-deoxyribonolactone in E.coli.

Lactate elicits vascular endothelial growth factor from macrophages: a possible alternative to hypoxia.

Macrophages respond to various stimuli to produce angiogenic factors but few mechanistic details are known. We examined the effects of hypoxia, lactate and nicotinamide on the expression of vascular endothelial growth factor by cultured macrophages. These agents were chosen because they down-regulate polyadenosine diphosphoribose levels. Following exposure, conditioned media were analyzed for vascular endothelial growth factor protein. Nicotinamide adenine dinucleotide, polyadenosine diphosphoribose, and vascular endothelial growth factor mRNA were measured in the cellular fraction. Angiogenic capacity of the conditioned media was tested in rabbit corneas and Matrigel implants. All three agents, hypoxia, lactate and nicotinamide, elicited significantly increased levels of vascular endothelial growth factor mRNA and vascular endothelial growth factor in the conditioned media, and these levels were paralleled by their angiogenic activity. Polyadenosine diphosphoribose in the cellular fraction was correspondingly depressed. Anti-vascular endothelial growth factor antibody inhibited most of the angiogenic response whereas anti-basic fibroblast growth factor antibody had little effect. We propose that redox changes associated with the alteration of cellular nicotinamide adenine dinucleotide and polyadenosine diphosphoribose are involved in lactate-mediated VEGF expression.

Jugular wave recognition breakthrough: X' descent vs the X descent and trough.

Irrational nomenclature and concentrating on ascents and peaks of waves have made recognition of jugular waves an occult art. By agreeing to call atrial relaxation X: and the systolic fall in atrial pressure due to the descent of the base X', we can begin to teach the easy recognition of jugular contours. Next, it is necessary to realize that the artifacts seen on electronically derived jugular pulse tracings are not to be expected when observing the neck pulsations with the naked eye. Finally, it can be shown that the easiest way to recognize jugular waves is by timing only descents as being either systolic or diastolic according to their relation to either the patient's radial pulse or heart sounds. It is almost unknown that only a single systolic descent due to the descent of the base is usual in the normal adult jugular.

Using internal jugular pulsations as a manometer for right atrial pressure measurements.

External jugulars are not reliable as an indication of right atrial pressure because of their passage through two right angles and also because they are often not visible. The top level of internal jugular pulsations which are transmitted to the skin of the neck serves as a pulsation manometer. A standard chest angle of 45 degrees and a standard zero at the sternal angle can be used together with a centimeter ruler to give a useful measurement of jugular venous pressure. The use of a carpenter level (spirit level) and a round-bottomed tongue blade measured off in centimeters will allow accurate follow-up. An increase in tone-volume can be detected by the abdominal compression test or abdominojugular test (also known by the outdated terminology of hepatojugular reflux).

The abasic site as a target for generation of locally multiply damaged sites.

Abasic sites in DNA have been specifically targeted by synthetic compounds able to cleave DNA at abasic sites and to induce photodamages in the vicinity of the lesion. The synthesis and the photoactivity of the drugs on abasic sites containing DNA and oligonucleotides are reported.

Synthesis and study of a new adenine-acridine tandem, inhibitor of exonuclease III.

A new heterodimer adenine-chain-acridine containing a mixed amido-guanidinium linker chain was synthesized. To achieve the synthesis a new method of introduction of aminoalkyl chain at position 9 of adenine was designed. The heterodimer interacts specifically with the abasic sites in DNA and inhibits the major base excision repair enzyme in Escherichia coli, Exonuclease III.

Relaxin induces vascular endothelial growth factor expression and angiogenesis selectively at wound sites.

Relaxin is a reproductive hormone that has historically been characterized as being responsible for pubic ligament loosening and cervical ripening. Recently, relaxin has been associated with neovascularization of the endometrial lining of the uterus, potentially via specific induction of vascular endothelial growth factor. Previously conducted clinical studies using partially purified porcine relaxin have described relaxin's ability to stimulate the healing of ischemic wounds, suggesting that relaxin may also have angiogenic effects at sites of ischemic wound healing. In the present study, relaxin's angiogenic effects in the context of wound repair were tested in rodent models of angiogenesis and wound healing. Relaxin showed an ability to stimulate new blood vessel formation, particularly at ischemic wound sites, and to induce both vascular endothelial growth factor and basic fibroblast growth factor specifically in cells, presumably including macrophages, collected from wound sites. Resident macrophages collected from nonwound sites, such as the lung, did not show altered expression of these cytokines following relaxin administration. Because angiogenic wound cells are frequently macrophages, THP-1 cells, a cell line of monocyte lineage that binds relaxin specifically, were tested for and shown to induce vascular endothelial growth factor and basic fibroblast growth factor in response to relaxin. In conclusion, relaxin may be useful in the treatment of ischemic wounds by stimulating angiogenesis via the induction of vascular endothelial growth factor and basic fibroblast growth factor in wound macrophages.

Abasic site recognition in DNA as a new strategy to potentiate the action of anticancer alkylating drugs?

Inhibition of abasic site repair in the cell seems an attractive strategy to potentiate the action of antitumor DNA alkylating drugs. Molecules that bind specifically and strongly to the abasic site are possible candidates to achieve such inhibition. We explored this strategy by preparing molecule 4 that incorporates (1) an aminoacridine intercalator for DNA binding, (2) an adenine moiety for abasic site recognition, and (3) a linker containing two guanidinium functions to increase binding to DNA without inducing cleavage at the base-sensitive abasic site. Compound 4 was compared to analogues containing secondary amines, i.e., 1. We report on synthesis of the new heterodimer 4. We show by physicochemical studies-including determination of association constants with calf-thymus DNA, T(m) measurements, and high-field NMR examination of the complexes formed with abasic DNA duplexes-that 4 binds specifically and more strongly to the abasic site than the analogues. Compound 4 does not cleave abasic plasmid DNA. Compound 4 shows apparent synergy with the anticancer bischloroethylnitrosourea (BCNU) in L1210 and A549 cell lines in vitro. It potentiates BCNU in the in vivo tests. The results favor the pertinence of the strategy.

The alcoholic cardiomyopathies--genuine and pseudo.

Two types of genuine alcoholic cardiomyopathies can produce congestive heart failure, an acute fulminate hyperkinetic type with high cardiac output and a hypokinetic type with a low cardiac output, both of which respond to thiamine. When the chronic alcoholic develops a dilated cardiomyopathy with congestive heart failure without a history of significant malnutrition, then they do not respond to thiamine. This may be explained by a study in which mice given a myotropic virus plus alcohol developed more frequent and severe viral cardiomyopathies than those not fed alcohol. This suggests that a chronic dilated cardiomyopathy in an alcoholic may not be the direct result of the alcohol but secondary to a viral myocarditis. This suggests that the preferred terminology for a dilated cardiomyopathy in an alcoholic who does not respond to thiamine and good nutrition should simply be a dilated cardiomyopathy in an alcoholic. We should assume that the cardiomyopathy is possibly of viral etiology.

A simple and sensitive method for in vitro quantitation of abasic sites in DNA.

A novel method for the quantitation of abasic sites (AP sites) in DNA is described. As abasic sites can be generated by controlled thermal treatment of base-modified DNA, this method can be used for estimation of the extent of DNA damage resulting from exposure to genotoxic agents. The method involves use of probe molecules 1 and 2 that contain a fluorescent label linked to an aminooxy group which reacts specifically with the aldehydic function of the ring-opened form of abasic sites. The two fluorescent probes 1 and 2 were found to react with 2-deoxyribose, a model substrate, at the optimum of pH 4.0. As spontaneous depurination occurs at low pH, the reactions with abasic DNA were carried out at neutral pH with an excess concentration of the probes. Studies with alkylated, depurinated calf thymus DNA showed that the method is selective and quantitative. Good correlations were found between the level of 7-methylguanine (7-MeGua), generated in vitro in DNA by the methylating agent dimethyl sulfate, and the amount of AP sites as determined by the method presented here. In addition, similar correlations were found when the assay was used to detect abasic sites in DNA isolated from rats treated with carcinogenic alkylating agents. In each case, the level of abasic sites, as expected, is slightly higher than the level of 7-MeGua which is known to represent about 70% of the total modifications of DNA following exposure to the methylating agent. This method may be useful not only in experimental settings but also in studies of DNA damage in humans resulting from chemotherapy or exposure to environmental agents.