Clinical Heart fAilure Management Program: Changing the practice by partnering primary care and specialists (CHAMP-HF)

Background

While significant gains were made in the management of heart failure (HF), most patients are still diagnosed when they are acutely ill in hospital, often with advanced disease. Earlier diagnosis in the community could lead to improved outcomes. Whether a partnership and an educational program for primary care providers (PCP) increase HF awareness and management is unknown.

Methods

We conducted an observational study between March 2019 and June 2020 during which HF specialists gave monthly HF conferences to PCP. Using a pre-post design, medical charts and administrative databases were reviewed and a questionnaire was completed by participating PCP. Primary and secondary endpoints included: 1) the number of patients diagnosed with HF, 2) implementation of GDMT for patients with HFrEF; 3) PCPs' experience and confidence.

Results

Six PCP agreed to participate. Amongst the 11,909 patients of the clinic, 70 (0.59 %) patients met the criteria for HF. This number increased by 28.6 % (n = 90) after intervention. Increased use of GDMT for HFrEF patients at baseline (n = 35) was observed for all class of agents, with doubling of patients on triple therapies, from 8 (22.9 %) to 16 (45.7 %), p = 0.0047. Self-confidence on HF management was low (1, 16.7 %) but increased after the educational intervention of physicians (3, 50 %).

Conclusion

An educational and collaborative approach between HF specialists and community PCP increased the number of new HF cases diagnosed, enhanced implementation of GDMT in patients with HFrEF and increase PCPs' confidence in treating HF, despite being conducted during the COVID-19 pandemic.

The contribution of inflammatory astrocytes to BBB impairments in a brain-chip model of Parkinson's disease

Astrocyte dysfunction has previously been linked to multiple neurodegenerative disorders including Parkinson's disease (PD). Among their many roles, astrocytes are mediators of the brain immune response, and astrocyte reactivity is a pathological feature of PD. They are also involved in the formation and maintenance of the blood-brain barrier (BBB), but barrier integrity is compromised in people with PD. This study focuses on an unexplored area of PD pathogenesis by characterizing the interplay between astrocytes, inflammation and BBB integrity, and by combining patient-derived induced pluripotent stem cells with microfluidic technologies to generate a 3D human BBB chip. Here we report that astrocytes derived from female donors harboring the PD-related LRRK2 G2019S mutation are pro-inflammatory and fail to support the formation of a functional capillary in vitro. We show that inhibition of MEK1/2 signaling attenuates the inflammatory profile of mutant astrocytes and rescues BBB formation, providing insights into mechanisms regulating barrier integrity in PD. Lastly, we confirm that vascular changes are also observed in the human postmortem substantia nigra of both males and females with PD.

Rapamycin-loaded Poly(lactic-co-glycolic) acid nanoparticles: Preparation, characterization, and in vitro toxicity study for potential intra-articular injection

Osteoarthritis (OA) is the most common degenerative joint disease. Rapamycin is a potential candidate for OA treatment by increasing the autophagy process implicated in its physiopathology. To optimize Rapamycin profit and avoid systemic side effects, intra-articular (i.a.) administration appeared helpful. However, Rapamycin's highly hydrophobic nature and low bioavailability made it challenging to develop purpose-made drug delivery systems to overcome these limitations. We developed Rapamycin-loaded nanoparticles (NPs) using poly (lactic-co-glycolic acid) by emulsion/evaporation method. We evaluated these NPs' cytocompatibility towards cartilage (chondrocytes) and synovial membrane cells (synoviocytes) for a potential i.a. administration. The in vitro characterization of Rapamycin-loaded NPs had shown a suitable profile for an i.a. administration. In vitro biocompatibility of NPs was highlighted to 10 µM of Rapamycin for both synoviocytes and chondrocytes, but significant toxicity was observed with higher concentrations. Besides, synoviocytes are more sensitive to Rapamycin-loaded NPs than chondrocytes. Finally, we observed in vitro that an adapted formulated Rapamycin-loaded NPs could be safe at suitable i.a. injection concentrations. The toxic effect of Rapamycin encapsulated in these NPs on both articular cells was dose-dependent. After Rapamycin-loaded NPs i.a. administration, local retention, in situ safety, and systemic release should be evaluated with experimental in vivo models.

The density of calretinin striatal interneurons is decreased in 6-OHDA-lesioned mice

Interneurons play a significant role in the functional organization of the striatum and some of them display marked plastic changes in dopamine-depleted conditions. Here, we applied immunohistochemistry on brain sections from 6-hydroxydopamine (6-OHDA) mouse model of Parkinson's disease and sham animals to characterize the regional distribution and the morphological and neurochemical changes of striatal interneurons expressing the calcium-binding protein calretinin (CR). Two morphological subtypes of calretinin-immunostained (CR +) interneurons referred, respectively, as small- and medium-sized CR + interneurons were detected in 6-OHDA- and sham-lesioned animals. The small cells (9-12 µm) prevail in the anterior and dorsal striatal regions; they stain intensely for CR and display a single slightly varicose and moderately arborized process. The medium-sized CR + interneurons (15-20 µm) are more numerous than the small CR + cells and rather uniformly distributed within the striatum; they stain weakly for CR and display 2-3 long, slightly varicose and poorly branched dendrites. The density of medium CR + interneurons is significantly decreased in the dopamine-depleted striatum (158 ± 15 neurons/mm³), when compared to sham animals (370 ± 41 neurons/mm³), whereas that of the small-sized CR + interneurons is unchanged (174 ± 46 neurons/mm³ in 6-OHDA-lesioned striatum and 164 ± 22 neurons/mm³ in sham-lesioned striatum). The nucleus accumbens is populated only by medium-sized CR + interneurons, which are distributed equally among the core and shell compartments and whose density is unaltered after dopamine denervation. Our results provide the first evidence that the medium-sized striatal interneurons expressing low level of CR are specifically targeted by dopamine denervation, while the small and intensely immunoreactive CR + cells remain unaffected. These findings suggest that high expression of the calcium-binding protein CR might protect striatal interneurons against an increase in intracellular calcium level that is believed to arise from altered glutamate corticostriatal transmission in Parkinson's disease.

Challenging development of storable particles for oral delivery of a physiological nitric oxide donor

Nitric oxide (NO) deficiency is often associated with several acute and chronic diseases. NO donors and especially S-nitrosothiols such as S-nitrosoglutathione (GSNO) have been identified as promising therapeutic agents. Although their permeability through the intestinal barrier have recently be proved, suitable drug delivery systems have to be designed for their oral administration. This is especially challenging due to the physico-chemical features of these drugs: high hydrophilicity and high lability. In this paper, three types of particles were prepared with an Eudragit® polymer: nanoparticles and microparticles obtained with a water-in-oil-in-water emulsion/evaporation process versus microparticles obtained with a solid-in-oil-in-water emulsion/evaporation process. They had a similar encapsulation efficiency (around 30%), and could be freeze-dried then be stored at least one month without modification of their critical attributes (size and GSNO content). However, microparticles had a slightly slower in vitro release of GSNO than nanoparticles, and were able to boost by a factor of two the drug intestinal permeability (Caco-2 model). Altogether, this study brings new data about GSNO intestinal permeability and three ready-to-use formulations suitable for further preclinical studies with oral administration.

Understanding the Thermodynamic Mechanisms Leading to the Binding of Albumin to Lipid Nanocapsules

Lipid nanocapsules (LNCs) are drug delivery platforms designed for different administration routes including intravenous delivery. Nanocarrier binding with plasma proteins such as albumin is an important factor that influences the pharmacokinetics of the drug and the drug delivery system. The aim of this paper was to characterize LNCs with different surface compositions and hydrophobicities to study their interactions with albumin: binary LNCs [oil-glyceryl trioctanoate (TG) and PEGylated surfactant macrogol 15-hydroxystearate (MHS)] and ternary LNCs (TG, MHS, and Span 80). Span was found to stabilize and decrease the LNC size. The formation of a stable LNC/albumin complex in the ground state was demonstrated. Thermodynamic parameters indicated that complex formation was exothermic and spontaneous, and the interactions involved van der Waals forces and hydrogen bond formation. Ternary LNCs showed higher affinity for albumin than did binary LNCs (affinity constant 10-fold higher). This study is the first report on the thermodynamic mechanisms that lead to the formation of a complex between albumin and organic nanoparticles with different surface architectures.

Intestinal absorption of S-nitrosothiols: Permeability and transport mechanisms

S-Nitrosothiols, a class of NO donors, demonstrate potential benefits for cardiovascular diseases. Drugs for such chronic diseases require long term administration preferentially through the oral route. However, the absorption of S-nitrosothiols by the intestine, which is the first limiting barrier for their vascular bioavailability, is rarely evaluated. Using an in vitro model of intestinal barrier, based on human cells, the present work aimed at elucidating the mechanisms of intestinal transport (passive or active, paracellular or transcellular pathway) and at predicting the absorption site of three S-nitrosothiols: S-nitrosoglutathione (GSNO), S-nitroso-N-acetyl-l-cysteine (NACNO) and S-nitroso-N-acetyl-d-penicillamine (SNAP). These S-nitrosothiols include different skeletons carrying the nitroso group, which confer different physico-chemical characteristics and biological activities (antioxidant and anti-inflammatory). According to the values of apparent permeability coefficient, the three S-nitrosothiols belong to the medium class of permeability. The evaluation of the bidirectional apparent permeability demonstrated a passive diffusion of the three S-nitrosothiols. GSNO and NACNO preferentially cross the intestinal barrier though the transcellular pathway, while SNAP followed both the trans- and paracellular pathways. Finally, the permeability of NACNO was favoured at pH 6.4, which is close to the pH of the jejunal part of the intestine. Through this study, we determined the absorption mechanisms of S-nitrosothiols and postulated that they can be administrated through the oral route.

Glutathione: Antioxidant Properties Dedicated to Nanotechnologies

Which scientist has never heard of glutathione (GSH)? This well-known low-molecular-weight tripeptide is perhaps the most famous natural antioxidant. However, the interest in GSH should not be restricted to its redox properties. This multidisciplinary review aims to bring out some lesser-known aspects of GSH, for example, as an emerging tool in nanotechnologies to achieve targeted drug delivery. After recalling the biochemistry of GSH, including its metabolism pathways and redox properties, its involvement in cellular redox homeostasis and signaling is described. Analytical methods for the dosage and localization of GSH or glutathiolated proteins are also covered. Finally, the various therapeutic strategies to replenish GSH stocks are discussed, in parallel with its use as an addressing molecule in drug delivery.

Striatal Neurons Expressing D1 and D2 Receptors are Morphologically Distinct and Differently Affected by Dopamine Denervation in Mice

The loss of nigrostriatal dopamine neurons in Parkinson’s disease induces a reduction in the number of dendritic spines on medium spiny neurons (MSNs) of the striatum expressing D₁ or D₂ dopamine receptor. Consequences on MSNs expressing both receptors (D₁/D₂ MSNs) are currently unknown. We looked for changes induced by dopamine denervation in the density, regional distribution and morphological features of D₁/D₂ MSNs, by comparing 6-OHDA-lesioned double BAC transgenic mice (Drd1a-tdTomato/Drd2-EGFP) to sham-lesioned animals. D₁/D₂ MSNs are uniformly distributed throughout the dorsal striatum (1.9% of MSNs). In contrast, they are heterogeneously distributed and more numerous in the ventral striatum (14.6% in the shell and 7.3% in the core). Compared to D₁ and D₂ MSNs, D₁/D₂ MSNs are endowed with a smaller cell body and a less profusely arborized dendritic tree with less dendritic spines. The dendritic spine density of D₁/D₂ MSNs, but also of D₁ and D₂ MSNs, is significantly reduced in 6-OHDA-lesioned mice. In contrast to D₁ and D₂ MSNs, the extent of dendritic arborization of D₁/D₂ MSNs appears unaltered in 6-OHDA-lesioned mice. Our data indicate that D₁/D₂ MSNs in the mouse striatum form a distinct neuronal population that is affected differently by dopamine deafferentation that characterizes Parkinson’s disease.

Hydroxyapatite microporous bioceramics as vancomycin reservoir: Antibacterial efficiency and biocompatibility investigation

AbstarctInfections after bone reconstructive surgery are a real therapeutic and economic issue for the modern health care system. As the pathogen (most often Staphylococcus aureus) is able to develop a biofilm inside the bone, local delivery of antibiotics is of interest since high drug concentrations would be delivered directly at the target place. In this context, this study evaluated a porous hydroxyapatite implant as biocompatible bone substitute and vancomycin-delivery system to prevent post-operative infections. A simple method of impregnation with optimised conditions insured a high antibiotic loading (up to 2.3 ± 0.3 mg/m²), with a complete in vitro release obtained within 1-5 days. Additionally, the bacteriostatic and bactericidal effects of vancomycin were retained after loading on hydroxyapatite, as demonstrated after challenge with a Staphylococcus aureus strain. Regarding the biocompatibility, a wound healing assay of pre-osteoblastic MC3T3-E1 cells exposed to various concentrations of vancomycin revealed a dose-dependent reduction in cell migration for antibiotic concentrations higher than 1 mg/mL. Meanwhile, cells were able to proliferate normally on vancomycin-loaded scaffolds, although cell initial adhesion was seriously impaired for scaffolds loaded with 2.3 mg/m² Loaded scaffolds could be stored up to three months at room temperature without any degradation of the antibiotic. Together, these results demonstrate the efficacy of these hydroxyapatite bone substitutes for local delivery of vancomycin in the context of bone infection.

In Situ Microparticles Loaded with S-Nitrosoglutathione Protect from Stroke

Treatment of stroke, especially during the first hours or days, is still lacking. S-nitrosoglutathione (GSNO), a cerebroprotective agent with short life time, may help if administered early with a sustain delivery while avoiding intensive reduction in blood pressure. We developed in situ forming implants (biocompatible biodegradable copolymer) and microparticles (same polymer and solvent emulsified with an external oily phase) of GSNO to lengthen its effects and allow cerebroprotection after a single subcutaneous administration to Wistar rats. Arterial pressure was recorded for 3 days (telemetry, n = 14), whole-blood platelet aggregation up to 13 days (aggregometry, n = 58), and neurological score, cerebral infarct size and edema volume for 2 days after obstruction of the middle cerebral artery by autologous blood clots (n = 30). GSNO-loaded formulations (30 mg/kg) induced a slighter and longer hypotension (-10 vs. -56 ± 6 mmHg mean arterial pressure, 18 h vs. 40 min) than free GSNO at the same dose. The change in pulse pressure (-50%) lasted even up to 42 h for microparticles. GSNO-loaded formulations (30 mg/kg) prevented the transient 24 h hyper-aggregability observed with free GSNO and 7.5 mg/kg-loaded formulations. When injected 2 h after stroke, GSNO-loaded microparticles (30 mg/kg) reduced neurological score at 24 (-62%) and 48 h (-75%) vs. empty microparticles and free GSNO 7.5 mg/kg and, compared to free GSNO, divided infarct size by 10 and edema volume by 8 at 48 h. Corresponding implants reduced infarct size and edema volume by 2.5 to 3 times. The longer (at least 2 days) but slight effects on arterial pressures show sustained delivery of GSNO-loaded formulations (30 mg/kg), which prevent transient platelet hyper-responsiveness and afford cerebroprotection against the consequences of stroke. In conclusion, in situ GSNO-loaded formulations are promising candidates for the treatment of stroke.

Nitric oxide-eluting scaffolds and their interaction with smooth muscle cells in vitro

Fabrication of scaffolds loaded with nitric oxide (NO) donors (S-nitrosoglutathione, GSNO, and isosorbide mononitrate, ISMN) with suitable cell compatibility and optimized properties for tissue-engineering applications is reported using "in situ" technique. Based on FDA-approved polymer, solvent and dosage forms, this gentle process allowed the incorporation of the GSNO labile drug into scaffolds made of either poly(lactide-co-glycolide) (PLGA) or PLGA/poly(ɛ-caprolactone) (PCL) blend. During scaffolds manufacturing process including washing cycles, NO donors were leached from scaffolds. However, GSNO and ISMN concentrations in the last washing medium (10(-7) M and 10(-4) M, respectively) were in the range of cell suitability for tissue engineering. Further morphological analyses indicated that smoother surfaces with fewer but bigger pores (compatible with cell penetration and ingrowth) were obtained with PLGA in comparison with PLGA/PCL scaffolds. Among all tested matrices, only unloaded PLGA and GSNO-loaded PLGA/PCL exhibited intermediate cell anchorage, with mitochondrial activity close to the control and an increase in protein content, a prognostic for scaffold cell colonization, defining them as promising candidates. Deeper analyses of these two scaffolds looking at intracellular redox balance through reactive oxygen species production, glutathione, S-nitrosothiols, and nitrite ions content exhibited GSNO-loaded PLGA/PCL as the best of all tested 3D scaffolds for tissue engineering.

[Which future in cardiovascular therapy for nitric oxide and its derivatives?]

Nitric oxide (NO) is involved in the regulation of several physiological processes such as vascular homeostasis. Exogenous NO supply offers major therapeutic interest, especially in the treatment of coronary artery disease, ischemic syndromes and other cardiovascular pathologies. Nevertheless, the administration of NO itself is limited by its short half-life. NO prodrugs have been marketed for decades, e.g. organic nitrates for angina pectoris. These prodrugs display undeniable advantages such as angina crisis relief and preconditioning effect. Nevertheless, they suffer from several drawbacks: toxicity, tolerance, endothelial dysfunction exacerbation. These negative effects are related to massive production of reactive species derived from oxygen or nitrogen, which trigger oxidative and nitrosative stress. New NO donors are under development to overcome those disadvantages, among which the S-nitrosothiols family seems especially promising.

S-nitrosation/denitrosation in cardiovascular pathologies: facts and concepts for the rational design of S-nitrosothiols

Nitric oxide (•NO) is a physiological mediator of vasorelaxation constitutively synthesized by endothelial nitric oxide synthase. Because •NO has a short half-life, it is stored by proteins through S-nitrosation reactions. S-nitrosation was recently defined as a post-translational modification of proteins for cellular signalling, as important as glycosylation and phosphorylation. Disulfide forming/ isomerizing enzymes like thioredoxin (Trx), protein disulfide isomerase (PDI), which are chaperone proteins, are implicated into transnitrosation reactions, which are the transfer of •NO from one cysteine residue to another one. Furthermore, Trx has been shown to denitrosate S-nitrosoproteins depending on its redox status. S-nitrosation of Trx on Cys residues apart from active site, under nitrosative or oxidative stresses, enhances its activity, thereby reducing intracellular reactive oxygen species. Trx and PDI have therefore an essential role for cell signalling control which leads, among other actions, to cardio and vasculo-protection. The diminution of either •NO synthesis or bioavailability is implicated into a large number of cardiovascular pathologies associated to hypoxia or vasoconstriction like, endothelial dysfunction, arterial hypertension and atherosclerosis. In order to mimic the physiological storage of •NO as S-nitrosothiols, the development of •NO donors should be based on the covalent S-NO bond. The chemical stabilisation of the S-NO bond and protection against enzymatically active proteins such as PDI//Trx are major points for the design of stable compounds. S-nitrosothiols entrapment in innovative formulations (films, gels, microparticles, nanoparticles) is an emerging field in order to stabilise and protect them, and to deliver •NO under a sustained release at the targeted site.

[Impact of personality on the alcohol withdrawal syndrome intensity: a preliminary study with the Cloninger's model]

INTRODUCTION

The personality of alcohol dependant patients as a factor influencing the intensity of the alcohol withdrawal syndrome has been seldom examined. Cloninger's biosocial model of personality describes four temperaments (novelty seeking, harm avoidance, reward dependence, persistence) which, except for persistence, are admittedly linked to specific central neurotransmitters, and three characters. Novelty seeking is linked with low levels of mesencephalic dopamine, harm avoidance with high levels of serotonin in the septo-hippocampic system and reward dependence with low levels of noradrenaline in the ascending pathways from the locus coeruleus to the limbic system. The same neurotransmitters pathways are known to be involved in alcohol withdrawal, with a decrease of dopaminergic activity in the mesolimbic system, a decrease of serotonergic activity in the nucleus accumbens and an increase of the noradrenergic system. In view of the similarities between the neurobiological systems involved in Cloninger's model and in the neurobiological changes occurring during the withdrawal period, one would expect to observe severe withdrawal symptoms more frequently for patients with high novelty seeking, low harm avoidance and low reward dependence.

METHODS

To test this hypothesis, alcohol dependent patients according to DSM IV classification criteria who have drunk in the last twenty four hours were included in the study and received a standardized withdrawal treatment. The withdrawal syndrome intensity was examined with repeated measures of CIWA-Ar, the scores of which were correlated with TCI-R.

RESULTS

Twenty eight patients, between 30 et 65 years old and drinking 22,2 +/- 12 standard drinks per day were included. Antidepressant drugs, benzodiazepines and neuroleptics treatment introduced before hospitalisation were stopped or decreased as much as possible. A correlation matrix was carried out between all the variables which could influence withdrawal intensity (age at the hospitalisation, age at the begining of the dependance, ratio between the time of the dependance and the patients' age, the number of alcohol withdrawals carried out and the number of standard drinks per day), and showed a positive correlation between the number of standard drinks per day and withdrawal intensity at day 3 (r=0.7, p<0.000), at day 4 (r=0.52, p<0.005), at day 7 (r=0.41, p<0.036) and at day 8 (r=0.44, p<0.02); as between the ratio between the time of the dependance and the patients' age and withdrawal intensity at day 2 (r=0.43, p<0.03) and at day 5 (r=0.5, p<0.01). Therefore, partial correlations were calculated between the dimensions of personality and withdrawal intensity. The study showed a positive correlation between withdrawal intensity and harm avoidance from day 5 onwards (r=0.6 and P<0.003 at day 5, r=0.59 and P<0.004 at day 6, r=0.56 and P<0.006 at day 7, r=0.66 and P<0.001 at day 8), a negative correlation between withdrawal intensity and reward dependence at day 7 and 8 (r=- 0.45 and P<0.037 at day 7, r=- 0.49 and P<0.02 at day 8) and a negative correlation between withdrawal intensity and persistence from day 6 onwards (r=- 0.5 and P<0.017 at day 6, r=- 0.5 and P<0.019 at day 7, r=- 0.51 and P<0.014 at day 8). No correlation was found between withdrawal intensity and novelty seeking. The same relevant results were found again with the 22 patients without anti-depressant drugs' population.

DISCUSSION

Personality dimensions seem to influence alcohol withdrawal intensity once the severe symptomatology is over, while high doses of anti withdrawal treatment in the first days of abstinence may decrease the influence of personality on withdrawal symptoms. The positive correlation between harm avoidance and withdrawal intensity seems to invalidate our neurobiological hypotheses, but can be explained by clinical observations and corroborate studies assessing the influence of personality in benzodiazepine withdrawal intensity and in pain perception. This result encourages the introduction of support therapy during withdrawal and a cognitive-behavioural therapy before withdrawal in order to decrease patients' sensitivity to anxiety. The negative correlation between reward dependence and withdrawal intensity confirms the neurobiological hypotheses, but the weak correlation demands to be cautious in the interpretation of the results. The negative correlation between persistence and withdrawal intensity was expected.

CONCLUSION

The characteristics associated with persistence seem to act as protective factors during alcohol withdrawal, whereas those associated with harm avoidance appear to increase the symptoms of alcohol withdrawal. In contrast, the neurobiological hypotheses are only partially confirmed.

Induction of base damages representing a high risk site for double-strand DNA break formation in genomic DNA by exposure of cells to DNA damaging agents

DNA repair is known as a defense mechanism against genotoxic insults. However, the most lethal type of DNA damages, double-strand DNA breaks (DSBs), can be produced by DNA repair. We have previously demonstrated that when long patch base excision repair attempts to repair a synthetic substrate containing two uracils, the repair produces DSBs (Vispe, S. and Satoh, M. S. (2000) J. Biol. Chem. 275, 27386-27392 and Vispe, S., Ho, E. L., Yung, T. M., and Satoh, M. S. (2003) J. Biol. Chem. 278, 35279-35285). In this synthetic substrate, the two uracils are located on the opposite DNA strands (separated by an intervening sequence stable at 37 degrees C) and represent a high risk site for DSB formation. It is not clear, however, whether similar high risk sites are also induced in genomic DNA by exposure to DNA damaging agents. Thus, to investigate the mechanisms of DSB formation, we have modified the DSB formation assay developed previously and demonstrated that high risk sites for DSB formation are indeed generated in genomic DNA by exposure of cells to alkylating agents. In fact, genomic DNA containing alkylated base damages, which could represent high risk sites, are converted into DSBs by enzymes present in extracts prepared from cells derived from clinically normal individuals. Furthermore, DSBs are also produced by extracts from cells derived from ataxia-telangiectasia patients who show cancer proneness due to an impaired response to DSBs. These results suggest the presence of a novel link between base damage formation and DSBs and between long patch base excision repair and human diseases that occur due to an impaired response to DSB.

15-Hydroxyprostaglandin dehydrogenase in the bovine endometrium during the oestrous cycle and early pregnancy

Prostaglandins (PG) are primary regulators of reproductive function. In ruminants, the relative production of PGE2and PGF2αdetermines the return to a new oestrous cycle or to the establishment of pregnancy in response to a viable embryo. PG action depends on biosynthesis, transport and interaction with their receptors, which are all expressed differentially during the oestrous cycle. PGs are, however, local mediators and thus the onsite degradation by enzymes such as 15-hydroxyprostaglandin dehydrogenase (HPGD), also known as 15-PGDH, is another factor to consider in the regulation of physiological action. Little information is available on PG catabolism in the endometrium during the oestrous cycle or early pregnancy. The purpose of this study was to clone the bovine 15-PGDH, produce the recombinant protein and generate a specific antibody to study its activity and its expression in the endometrium during the oestrous cycle. We have found that the bovine 15-PGDH is highly homologous to the rat and human isoforms. 15-PGDH is localized principally in the glandular epithelium and to a lesser extent in stromal and luminal epithelial cells. The enzyme expression is regulated during the oestrous cycle and it reaches its maximal level on days 16–18. Transient expression is observed in luminal epithelial and trophoblast cells on day 21 of pregnancy. The mRNA is expressed at a constant high level throughout the cycle. The activity of the recombinant 15-PGDH was also tested and was found comparable for PGF2αand PGE2. These data suggest that 15-PGDH contributes to the tight regulation of PG action in the endometrium especially at the critical period of recognition of pregnancy.

Relationship between axonal collateralization and neuronal degeneration in basal ganglia

In this paper we evaluate the hypothesis of a possible link between the degree of axonal collateralization of neurons located within the different components of basal ganglia and the vulnerability of these neurons to neurodegenerative or neurotoxic events. Our results stemmed from single-cell labeling experiments in rodents and primates, immunohistochemical study of the dopaminergic nigrostriatal pathway in parkinsonian monkeys, and immunocytological analysis of the human striatum in normal individuals and in patients with Huntington's disease. Our results indicate that projection neurons within virtually all basal ganglia components are endowed with a widespread and highly collateralized axon that yields a fixed number of terminals. Such a high degree of axonal collateralization allows exquisitely precise interactions between the various basal ganglia nuclei. However, the maintenance of this unique morphological trait implies high-energy consumption and renders basal ganglia neurons highly vulnerable to neurodegenerative, metabolic or neurotoxic insults.

Paucisymptomatic brainstem lesions revealing CNS schistosomiasis

We describe clinical and magnetic resonance (MR) features in a 69-year-old, Caucasian woman presenting with an unusual meningeal onset of cerebral schistosomiasis. Magnetic resonance work-up demonstrated supra- and infratentorial lesions with prominent brainstem involvement contrasting with the paucisymptomatic clinical presentation. Because of a recent stay in Uganda, including swimming in Lake Victoria, a diagnosis of neuroschistosomiasis was suggested. Serological tests and rectal biopsy confirmed the putative diagnosis. The patient was successfully treated with praziquantel at a dose of 50 mg/kg/day for 15 days. Brain MRI abnormalities improved dramatically within two months.

Carcinome à petites cellules de l'ovaire hypercalcémiant révélé par un épisode de pancréatite aiguë : à propos d'un cas

Small cell carcinoma of the ovary of the hypercalcemic type is a rare tumour, usually lethal and occurring almost exclusively in young patients. In the majority of described cases, signs of this lesion were revealed by the associated hypercalcemia or by virtue of the physical tumour bulk alone. We report the first case of ovarian small cell carcinoma of the hypercalcemic revealed by a severe acute pancreatitis in a 19-year-old patient.

Poly(ADP-ribose) polymerase-1 is a negative regulator of HIV-1 transcription through competitive binding to TAR RNA with Tat.positive transcription elongation factor b (p-TEFb) complex

Human immunodeficiency virus, type 1 (HIV-1) transcription is regulated by a virus-encoded protein, Tat, which forms a complex with a host cellular factor, positive transcription elongation factor b (P-TEFb). When this complex binds to TAR RNA synthesized from the HIV-1 long terminal repeat promoter element, transcription is trans-activated. In this study we showed that, in host cells, HIV-1 transcription is negatively regulated by competition of poly(ADP-ribose) polymerase-1 (PARP-1) with Tat.P-TEFb for binding to TAR RNA. PARP-1, which has a high affinity for TAR RNA (K(D) = 1.35 x 10(-10) M), binds to the loop region of TAR RNA and displaces Tat or Tat.P-TEFb from the RNA. In vitro transcription assays showed that this displacement leads to suppression of Tat-mediated trans-activation of transcription. Furthermore in vivo expression of luciferase or destabilized enhanced green fluorescent protein genes under the control of the HIV-1 long terminal repeat promoter was suppressed by PARP-1. Thus, these results suggest that PARP-1 acts as a negative regulator of HIV-1 transcription through competitive binding with Tat or the Tat.P-TEFb complex to TAR RNA.

Camptothecin-sensitive Relaxation of Supercoiled DNA by the Topoisomerase I-like Activity Associated with Poly(ADP-ribose) Polymerase-1

Poly(ADP-ribose) polymerase-1 is a highly abundant nuclear enzyme implicated in transcription, DNA replication, and DNA repair through binding of nascent RNA and interactions with various factors. We found that purified fractions of recombinant human poly(ADP-ribose) polymerase-1 expressed in Escherichia coli possess yet another activity, a Mg(2+)-dependent DNA supercoil relaxation activity. Cleavage of recombinant poly(ADP-ribose) polymerase-1 by caspase-3, an apoptotic protease, reduced this activity, as did the removal of either of the two zinc finger motifs located in the N-terminal DNA-binding domain of poly(ADP-ribose) polymerase-1. In addition, this activity was separated from E. coli topoisomerase I by gel-filtration column chromatography, suggesting that this activity is specifically associated with poly(ADP-ribose) polymerase-1. Because this relaxation activity did not require ATP and was resistant to VP16, a topoisomerase II inhibitor, this activity is closer to that of topoisomerase I. However, the supercoiled DNA relaxation activity associated with poly(ADP-ribose) polymerase-1 is distinct from that of human or E. coli topoisomerase I, as this activity could not completely remove superhelical tensions from plasmid DNA. Thus, we referred to this activity as topoisomerase I-like activity. This Mg(2+)-dependent DNA supercoil relaxation activity was found to be sensitive to camptothecin, a mammalian topoisomerase I inhibitor.

Major histocompatibility complex class I and II expression on macrophages containing a virulent strain of Brucella abortus measured using green fluorescent protein-expressing brucellae and flow cytometry

Immune responses appropriate for control of an intracellular pathogen are generated in mice infected with Brucella abortus, shown by the ability of T cells to adoptively transfer resistance to naive mice. The infection nevertheless persists for months. It was hypothesized that one factor in maintaining the infection despite the presence of immune T cells was suboptimal expression of major histocompatibility complex (MHC) molecules on macrophages containing brucellae. This would allow B. abortus to elude detection by the host's immune system. To test this, B. abortus organisms expressing green fluorescent protein (GFP-Brucella) were constructed and three-color flow cytometry used to evaluate MHC expression on macrophages following in vitro or in vivo infection. When infected in vitro, the levels of MHC class I and class II expression on J774 macrophages containing GFP-Brucella were the same or higher than on macrophages without GFP-Brucella in the same cultures. Similarly, the MHC expression was higher on GFP(+) peritoneal exudate cells following infection or phagocytosis of heat-killed GFP-Brucella than it was on uninfected peritoneal exudate cells. Following in vivo infection of mice the level of MHC class I and II expression on GFP(+) cells in their spleens (the main site of infection) also tended to be as high as or higher than that on the GFP-negative cells. The only in vivo GFP(+) cells that showed a decreased MHC expression was a population of splenic Mac1(+) cells recovered from interferon-gamma gene-disrupted mice at the time of their death due to an overwhelming number of bacteria per spleen. Overall, it was concluded that decreased MHC expression is not a general principle associated with brucella infection of macrophages and thus not likely to contribute to maintenance of the chronic infection.

Immune control of Brucella abortus 2308 infections in BALB/c mice

BALB/c mice infected with Brucella abortus strain 2308 have 10-fold higher levels of bacteria during the plateau phase of infection (the time period when the number of colony-forming units in vivo remains consistent) than the more resistant C57BL/10 mice. This is due to a cessation of interferon-gamma (IFN-gamma) production that begins after the first week of infection and continues until the end of the plateau phase at least 6 weeks post infection. Despite the lack of IFN-gamma production during this time BALB/c mice are able to prevent an increase in bacterial colony-forming units. Here it was shown that both tumor necrosis factor (TNF)-alpha and CD8 T cells were involved in controlling bacterial numbers in BALB/c mice during this time. That is, neutralization of TNF-alpha or depletion of CD8 T cells with monoclonal antibodies resulted in a significant increase in the number of splenic colony-forming units recovered at 3 weeks post infection. In the absence of CD8 T cells there was also a significant increase in splenic macrophages. The role of TNF-alpha may depend upon the presence of interferon-gamma early in the infection since when TNF-alpha was neutralized in interferon-gamma gene knockout mice there was a marked increase in splenic macrophages, NK cells and neutrophils but not a significant increase in colony-forming units.

Two types of projection neurons in the internal pallidum of primates: single-axon tracing and three-dimensional reconstruction

The axonal projections of the internal pallidum (GPi) in cynomolgus monkeys (Macaca fascicularis) were studied by labeling small pools of neurons with biotinylated dextran amine. Fifty-two axons were reconstructed entirely from serial sections with a camera lucida. Two types of projection neurons were identified in the GPi on the basis of their target sites. The abundant and centrally located type I neurons gave rise to a long axonal branch that descended directly to the pedunculopontine tegmental nucleus, where it arborized discretely. Other branches ascended to the thalamus and broke into 10-15 thinner collaterals that ran through most of the ventral anterior nucleus, where they terminated as typical plexuses. About half of these axons gave rise to collaterals that arborized in both components of the centre médian/parafascicular thalamic complex. The less numerous and peripherally located type II neurons had an axon that climbed the rostral thalamic pole, coursed along the stria medullaris, and arborized profusely within the lateral habenular nucleus, which stood out as the most densely innervated pallidal target. Some type II axons provided collaterals to the anterior thalamic nuclei. A small proportion of axons of both types had branches that crossed the midline and terminated in contralateral GPi target structures. Three-dimensional reconstruction showed that type I axons arborized principally along the sagittal plane. These data reveal that GPi neurons of type I act through a widely distributed axonal network upon thalamic and brainstem premotor neurons, whereas type II neurons act in a much more focused manner upon lateral habenular neurons.

A re-evaluation of the current model of the basal ganglia

The current model of basal ganglia organization has been developed progressively over the last two decades in the light of key observations made at both experimental and clinical levels. This model has been highly successful in that it has stimulated a large amount of research in the field. However, several experimental and clinical findings that are at odds with the model have accumulated during the last decade. This paper reviews some of our own single-axon tracing studies in primates, which call for a re-evaluation of the current basal ganglia model.

Application of capillary electrophoresis with laser-induced fluorescence detection to the determination of biogenic amines and amino acids in brain microdialysate and homogenate samples

A procedure is described to derivatize 16 primary-amine-containing biogenic amines and amino acids in brain mixtures with the fluorogenic reagent 5-furoylquinoline-3-carboxaldehyde (FQ). These FQ-tagged compounds in the brain sample were resolved in less than 16 min based on micellar electrokinetic chromatography and laser-induced fluorescence. There was a linear relationship between the concentration of analyte and the fluorescence intensity, with correlation coefficients in the range of 0.96-1.00. The utility of this method for the quantification of the important inhibitory neurotransmitter gamma-aminobutyric acid in microdialysates and brain homogenates from rats is illustrated.

Information technologies, health, and "globalization": anyone excluded?

Modern information technologies and worldwide communication through the Internet promise both universal access to information and the globalization of the medico-social network s modes of communication between doctors, laboratories, patients, and other players. The authors, specialists in public health and members of an association that aims to create opportunities for access to training in public health in developing countries, warn that the use of the term "globalization" ignores the reality of the "digital divide," that is, the fact that social inequalities may preclude the realization of this promise on a truly global scale.

Analysis of amino acids and catecholamines, 5-hydroxytryptamine and their metabolites in brain areas in the rat using in vivo microdialysis

In vivo microdialysis, using dialysis probes inserted into discrete brain areas and subsequent analysis of neurotransmitters and related substances in the dialysates (usually with HPLC), has yielded a great deal of important information about the actions of psychotropic drugs and endogenous neurotransmitter systems and about the functional interactions between various brain areas. This paper reviews the principles involved in in vivo microdialysis, its advantages and disadvantages, and recent innovations in methodology and applications. The first section includes brief discussions of principles and applications of dialysis, use of anesthetized versus conscious freely moving animals, and methods used to determine the neural origin of neurotransmitters in the dialysate. The subsequent sections provide detailed descriptions, based largely on our own studies in rats, of stereotaxic surgery, in vivo microdialysis, and dialysate analysis, with an emphasis on amino acids and biogenic amines and their metabolites. A discussion of methodological problems which may be encountered in the analysis of amino acids and biogenic amines is also included.

[Randomized controlled trial of medical and medico-surgical treatment of Hansen's neuritis]

The aim of the study was to compare the results of the medical treatment alone and of the medico-surgical treatment on leprous neuritis. The patients were followed-up during 2 years, with regular neurological evaluations. The statistical study was performed using the Tukey test. Ninety-three nerves (ulnar, median, common peroneal and posterior tibial) with a deficit of less than 6 months duration have been studied in 31 leprosy patients. All the patients were treated by steroids but in some of them a nerve surgical decompression was performed. An improvement of the sensitive and motor deficit was observed in both groups. No significant statistical differences appeared between the 2 groups according to the nerve involved, the duration of the deficit, the form of leprosy and the type of antibacillary treatment. However, the medico-surgical treatment had a significant better result on pain and on major but incomplete nervous involvement. This study included a limited number of nerves, thus, it would be useful to perform others randomized assays to better define the indications of surgical decompression in the management of leprous neuritis.

Organization of the basal ganglia: the importance of axonal collateralization

Recent neuroanatomical data obtained with single-axon or single-cell labeling procedures in both rodents and primates have revealed the presence of various types of projection neurons with profusely collateralized axons within each of the major components of the basal ganglia. Such findings call for a reappraisal of current concepts of the anatomical and functional organization of the basal ganglia,which play such a crucial role in the control of motor behavior. The basal ganglia now stand as a widely distributed neuronal network, whose elements are endowed with a highly patterned set of axon collaterals. The elucidation of this finely tuned network is needed to understand the complex spatiotemporal sequence of neural events that ensures the flow of cortical information through the basal ganglia.

Axonal branching pattern of neurons of the subthalamic nucleus in primates

Axonal projections arising from the subthalamic nucleus (STN) in cynomolgus monkeys (Macaca fascicularis) were traced after labeling small pools (5-15 cells) of neurons with biotinylated dextran amine. Seventy-five single axons were reconstructed from serial sagittal sections with a camera lucida. Most of the STN labeled cells displayed five to eight long, sparsely spined dendrites that arborized mostly along the main axis of the nucleus. Based on their axonal targets, five distinct types of STN projection neurons have been identified: 1) neurons projecting to the substantia nigra pars reticulata (SNr), the internal (GPi) and external (GPe) segments of the globus pallidus (21.3%); 2) neurons targeting SNr and GPe (2. 7%); 3) neurons projecting to GPi and GPe (48%); 4) neurons targeting GPe only (10.7 %); and 5) neurons with axons that coursed toward the sriatum, but whose terminal arborization could not be visualized in detail (17.3%). Axons of the first two types bifurcated into rostral subthalamopallidal and caudal pallidonigral branches. However, the majority of STN axons had only a single branch that coursed rostrally toward the pallidum and striatum. These results reveal that, in contrast to current beliefs, the primate STN is not a monolithic entity. This nucleus harbors several subtypes of projection neurons, each endowed with a highly patterned set of collaterals. This organization allows STN neurons to exert a multifarious effect not only on the GPe, with which the STN is reciprocally connected, but also on the two major output structures of the basal ganglia, the SNr and the GPi.