BAER-101, a selective potentiator of α2- and α3-containing GABAA receptors, fully suppresses spontaneous cortical spike-wave discharges in Genetic Absence Epilepsy Rats from Strasbourg (GAERS)

BAER-101 (formerly AZD7325) is a selective partial potentiator of α2/3-containing γ-amino-butyric acid A receptors (GABAARs) and produces minimal sedation and dizziness. Antiseizure effects in models of Dravet and Fragile X Syndromes have been published. BAER-101 has been administered to over 700 healthy human volunteers and patients where it was found to be safe and well tolerated. To test the extent of the antiseizure activity of BAER-1010, we tested BAER-101 in the Genetic Absence Epilepsy Rats from Strasbourg (GAERS) model, a widely used and translationally relevant model. GAERS rats with recording electrodes bilaterally located over the frontal and parietal cortices were used. Electroencepholographic (EEG) signals in freely moving awake rats were analyzed for spike-wave discharges (SWDs). BAER-101 was administered orally at doses of 0.3-100 mg/kg and diazepam was used as a positive control using a cross-over protocol with a wash-out period between treatments. The number of SWDs was dose-dependently reduced by BAER-101 with 0.3 mg/kg being the minimally effective dose (MED). The duration of and total time in SWDs were also reduced by BAER-101. Concentrations of drug in plasma achieved an MED of 10.1 nM, exceeding the Ki for α2 or α3, but 23 times lower than the Ki for α5-GABAARs. No adverse events were observed up to a dose 300× MED. The data support the possibility of antiseizure efficacy without the side effects associated with other GABAAR subtypes. This is the first report of an α2/3-selective GABA PAM suppressing seizures in the GAERS model. The data encourage proceeding to test BAER-101 in patients with epilepsy.

Pronounced antiseizure activity of the subtype-selective GABAA positive allosteric modulator darigabat in a mouse model of drug-resistant focal epilepsy

Aim

Darigabat is an α2/3/5 subunit‐selective positive allosteric modulator of GABA_A receptors that has demonstrated broad‐spectrum activity in several preclinical models of epilepsy as well as in a clinical photoepilepsy trial. The objective here was to assess the acute antiseizure effect of darigabat in the mesial temporal lobe epilepsy (MTLE) mouse model of drug‐resistant focal seizures.

Methods

The MTLE model is generated by single unilateral intrahippocampal injection of low dose (1 nmole) kainic acid in adult mice, and subsequent epileptiform activity is recorded following implantation of a bipolar electrode under general anesthesia. After a period of epileptogenesis (~4 weeks), spontaneous and recurrent hippocampal paroxysmal discharges (HPD; focal seizures) are recorded using intracerebral electroencephalography. The number and cumulated duration of HPDs were recorded following administration of vehicle (PO), darigabat (0.3–10 mg kg⁻¹, PO), and positive control diazepam (2 mg kg⁻¹, IP).

RESULTS

Darigabat dose‐dependently reduced the expression of HPDs, demonstrating comparable efficacy profile to diazepam at doses of 3 and 10 mg kg⁻¹.

CONCLUSIONS

Darigabat exhibited a robust efficacy profile in the MTLE model, a preclinical model of drug‐resistant focal epilepsy. A Phase II proof‐of‐concept placebo‐controlled, adjunctive‐therapy trial (NCT04244175) is ongoing to evaluate efficacy and safety of darigabat in patients with drug‐resistant focal seizures.

French neonatal society position paper stresses the importance of an early family-centred approach to discharging preterm infants from hospital

AIM

The families of hospitalised preterm infants risk depression and post-traumatic stress and the preterm infants risk re-hospitalisation. The French neonatal society's aim was to review the literature on how the transition from hospital to home could limit these risks and to produce a position paper.

METHODS

A systematic literature review was performed covering 1 January 2000 to 1 January 2018, and multidisciplinary experts examined the scientific evidence.

RESULTS

We identified 939 English and French papers and 169 are quoted in the position paper. Most studies stressed the importance of early, personalised and progressive involvement of the family. Healthcare staff and families should assess discharge preparations jointly. This evaluation should assess the capacities of the newborn infant, with regard to its physiological maturity. It should also assess the family's ability to supply the medical, psychological and social assistance required before and after discharge. There should be a structured follow-up process that includes effective communication, various tools, interventions, networks, health and social professionals.

CONCLUSION

Discharge preparations may improve the transition from hospital to home and the outcomes for the parents and newborn preterm infant. This early family-centred approach should be structured, coordinated and based on individual needs and circumstances.

Recommendation for hygiene and topical in neonatology from the French Neonatal Society

We sought to establish guidelines for hygiene care in newborns based on a systematic review of the literature and grading of evidence using the Groupe de Réflexion et d'Evaluation de l'Environement des Nouveau-nés (GREEN) methodology. We examined 45 articles and 4 reports from safety agencies. These studies recommend a tub bath (rather than a sponge bath) for full-term infants and a swaddle bath for preterm newborns. They also recommend against daily cleansing of preterm infants. The literature emphasized that hygiene care must consider the clinical state of the newborn, including the level of awareness and behavioral responses. Hospitalized newborns treated with topical agents may also experience high exposure to potentially harmful excipients of interest. Caregivers should therefore be aware of the excipients present in the different products they use. In high-resource countries, the available data do not support the use of protective topical agents for preterm infants.Conclusions: We recommend individualization of hygiene care for newborns. There is increasing concern regarding the safety of excipients in topical agents that are used in neonatology. A multidisciplinary approach should be used to identify an approach that requires lower levels of excipients and alternative excipients. What is known: • Hygiene care is one of the most basic and widespread types of care received by healthy and sick newborns worldwide. • There is no current guideline on hygiene for preterm or hospitalized term newborn. What is new: • The French Group of Reflection and Evaluation of the environment of Newborns (GREEN) provided here guidelines based on the current body of evidence. • Caregivers should be aware of the many issues related to hygiene care of newborns including newborns' behavioral responses to hygiene care, exposition to excipients of interest, and the potential risk of protective topical agents in a preterm infant. provided here guidelines based on the current body of evidence. • Caregivers should be aware of the many issues related to hygiene care of newborns including newborns' possible behavioral responses to hygiene care, exposition to excipients of interest and the potential risk of protective topical agents in a preterm infant.

Pronounced antiepileptic activity of the subtype-selective GABAA -positive allosteric modulator PF-06372865 in the GAERS absence epilepsy model

AIM

Antiepileptic drugs that modulate GABA have the potential to aggravate or improve the symptoms of absence epilepsy. PF-06372865 is a positive allosteric modulator (PAM) of α2/3/5 subunit-containing GABA_A receptors with minimal activity at α1-containing receptors, which are believed to mediate many of the adverse events associated with benzodiazepines. The aim of this study was to assess the antiepileptic effect of PF-06372865 in a preclinical model of absence seizures.

METHODS

Genetic absence epilepsy rats from Strasbourg (GAERS) was implanted with four cortical electrodes over the frontoparietal cortex, and the number and cumulated duration of spike-and-wave discharges (SWDs) were recorded for 10-90 minutes following administration of vehicle, PF-06372865, and positive controls diazepam and valproate.

RESULTS

PF-06372865 (0.3, 1, 2, 10 mg kg^-1 ) dose-dependently reduced the expression of SWDs, including full suppression at the highest doses by 30 minutes after administration.

CONCLUSIONS

PF-06372865 demonstrated robust efficacy in suppressing SWDs in the GAERS model of absence epilepsy. To our knowledge, this is the first demonstration of antiepileptic activity of an α2/3/5-subtype-selective GABA_A PAM in a model of absence epilepsy. Further study of the antiepileptic properties of PF-06372865 is warranted in patients with absence seizures.

Abstract P3-12-03: Impact of genetic polymorphisms on plasma levels of tamoxifen and its metabolites and toxicity: 6-months results of the adjuvant breast cancer longitudinal PHACS study (NCT01127295)

Supported by a PHRC grant (#09-18-005)

Background: The role of CYP2D6 genetic polymorphisms and plasma levels of active metabolites of tamoxifen (TAM) on clinical response and occurrence of side effects remains controversial. We conducted a prospective, adjuvant, multicentre, 3-year follow-up study of breast cancer patients in order to evaluate the relationships between pharmacogenetics, pharmacokinetics and toxicity of TAM and its metabolites (n=879) or aromatase inhibitors (AI, n=1098). The present report focuses on the evaluation at 6 months after inclusion of 864 patients treated with 20 mg/day TAM.The clinical results and the AI PG/PK analyses are described elsewhere (abstracts #851544 and #851525).

Methods: Residual plasma concentrations for tamoxifen and its 6 major metabolites (endoxifen ENDO, 4-hydroxy-tamoxifen 4-OH-TAM, N-desmethyl TAM, TAM-N-oxyde, 4'-OH-TAM and Z'ENDO) at 6 months after start of treatment were measured by UPLC-MS/MS in 789 patients. Nine patients with TAM concentrations below the limit of quantification were excluded for non-compliance. SNP genotyping of 95 selected SNPs was performed on the Biomark (Fluidigm) in a microfluidic multiplex 96 dynamic array chip with Taqman assays and was available for 857 patients. Patients were classified according to their CYP2D6 metaboliser status (MS) (PM, IM, EM and UM) based on presence of functional, decreased function or no functional alleles (*4, *6, *7, *9, *10, *17, *41) and number of CYP2D6 copies (*5 or duplication). Metabolic ratios (MR) were calculated for TAM/4-OH-TAM, TAM/N-desmethyl tamoxifen (NDT), NDT/ENDO and 4-OH-TAM/ENDO. Anti-estrogenic activity score (AAS) was calculated according to a recently proposed algorithm (De Vries Schultink et al.,Breast Cancer Res Treat. 2017).Toxicity was measured as a binary outcome (first occurrence or worsening of hot flushes, fatigue, depression, pain, arthralgia, vaginal dryness). All genetic associations were adjusted for multiple testing.

Results: ENDO concentration and AAS increased significantly with CYP2D6 MS (p<0.001). The presence of a CYP3A4*22 allele was significantly associated with endoxifen concentrations; this association remained significant after adjusting for CYP2D6 MS. TAM/4-OH-TAM MR was significantly influenced by the presence of CYP3A4*22, CYP2C19*2 and *17, and CYP2D6 status. The percentage of patients having an AAS>=1798 (i.e., threshold previously associated with recurrence-free survival RFS by De Vries et al. 2017) was 6%, 50%, 84% and 91% of patients respectively classified as PM, IM, EM and UM. Side effects were not significantly associated with higher levels of TAM metabolites concentrations. After correction for multiple testing, SNPs or CYP2D6 MS were not significantly associated with occurrence or worsening of adverse events, premature treatment discontinuations or switch due to toxicity within the first 6 months.

Conclusions: In this large prospective study, we quantified the impact of PG on TAM PK and AAS, previously shown to predict RFS. Although the toxicity observed after 6 months of TAM does not seem correlated with PK or PG, these relationships need to be re-evaluated during the 3-year follow-up.

Citation Format: White-Koning M, Arellano C, Le Morvan V, Evrard A, Puzskiel A, Vachoux C, Dauba J, Houyau P, Poublanc M, Robert J, Boyer J-C, Roché H, Thomas F, Chatelut E. Impact of genetic polymorphisms on plasma levels of tamoxifen and its metabolites and toxicity: 6-months results of the adjuvant breast cancer longitudinal PHACS study (NCT01127295) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-12-03.

Abstract P3-12-10: First 6-month report of the longitudinal PHACS study (Pharmacology and Hormonotherapy (HT) for Adjuvant breast Cancer (BC) Study, NCT01127295)

Background: BC is a hormone-dependent disease for 75% of pts. HT is used in both adjuvant and metastatic settings for hormone–receptor (HR) positive tumors. In adjuvant situation, a 5-year HT period at least is recommended. Side-effects (SE) frequently alter quality of life and compliance, reducing the well-known benefits in risks of relapses and specific deaths. Underlying mechanisms are well understood for estrogen deprivation-induced events such as hot flashes, but little is known on arthralgia under aromatase inhibitors (AI). So, pharmacogenomics (PG), pharmacokinetics (PK), potential medications interactions are of value to explain individual drugs exposures, possible related side-effects and compliance to treatment.

Methods: We performed a prospective, multicenter, longitudinal study registering early clinical outcomes and SE during the first 3 years of adjuvant HT with tamoxifen (T) or AI. All tumors expressed at least one HR (>10%). The choice of HT molecule and one-drug or sequential treatment were left to the investigator. Pts were followed every 6 months with clinical examination by the referent oncologist and PK sampling each time. Biologic research consisted in PG investigations of different genes involved in the PK and pharmacodynamics of T and AI (95 SNPs) at baseline. SE, concurrent medications and compliance were registered by both the pts on a diary card and the physician. Evaluation was done only on new occurrence or increased grade of symptoms.

Results: This first report focuses on characteristics of the population and the results after the 6 first months of treatment. Between June 2010 and October 2014, 23 centers recruited 2000 pts. 23 were excluded leaving 1977 fully evaluable women; 879 (44%) started with T, 1098 (55%) with AI (554 letrozole (L), 390 anastrozole (A), 154 exemestane (E)). 56% of them had previously received chemotherapy, 96% radiotherapy and 8% trastuzumab.

Main characteristics were well balanced between the 2 classes of drugs; T was given mainly for pre- or perimenopausal pts. Most frequent co-morbidities were hypertension (8% T, 31% AI) and dyslipidemia or diabetes (T 11%, AI 26%). To note, almost 30% of pts described arthralgias at entrance and 37% had hot flashes.

At 6 months, 122 pts (6%; 43 T, 79 AI) had stopped treatment mainly for toxicity (11 T; 12 AI), progression or death (7 T; 4 IA), personal reasons (15 T; 37AI); 4 asked for changing T and 52 AI (equally for the 3 drugs). All these events were significantly more frequent for AI pts (p=0.042) and with E within the AI class (p<0.001).

Main changes in onset or increased intensity of symptoms concerned hot flushes with all drugs (30%), asthenia (20%), insomnia (20%), weight gain (17%), arthralgias (15% for T, 30% for AI), thrombotic events (24 of which 11 with T). 3 grade3 SAE HT-related were reported.

Biological data are reported in 2 other abst. (M. White-Koning. abst.#850248, F. Thomas, abst.#851525).

Conclusions: These preliminary data on the first 6-months exposure to HT on adjuvant setting in the real-life confirm early rates of withdraws and toxicities. Longer follow-up and subsequent PK analysis should help to understand persistent side-effects and reasons for non-compliance to adjuvant HT.

Citation Format: Roché H, Venat-Bouvet L, Debled M, Jacot W, Suc E, Dalenc F, Molnar-Stanciu D, Dohollou N, Franck D, Ferrer C, Laharie-Mineur H, Lavau-Denes S, Massabeau C, Mauries V, Robert J, Pinguet F, Marquet P, Evrard A, Chatelut E, Filleron T. First 6-month report of the longitudinal PHACS study (Pharmacology and Hormonotherapy (HT) for Adjuvant breast Cancer (BC) Study, NCT01127295) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-12-10.

Abstract P3-12-07: Pharmacogenetic determinants of aromatase inhibitors pharmacokinetics and side effects: 6-month results of the adjuvant breast cancer longitudinal PHACS study (NCT01127295)

Supported by a PHRC grant (#09-18-005)

Background: Recent literature has suggested that germline genetic variants of drug-metabolizing enzymes or CYP19A1 (coding for aromatase) may be involved in the systemic aromatase inhibitors (AI) concentrations or the occurrence of side effects (Hertz et al. Pharmacogenomics 2017). A prospective multicentre 3-year follow-up study was carried out to investigate the relationships between pharmacogenetics (PG), pharmacokinetics (PK) and toxicity in breast cancer patients treated with adjuvant AI (n=1098) or tamoxifen (n=879). The clinical results and the tamoxifen PG/PK analyses are described elsewhere (abstracts #851544 and #850248).

Methods: SNP genotyping of 95 SNPs was performed on the Biomark (Fluidigm) with Taqman assays and was available for 373, 515 and 151 patients treated with anastrozole (ANA), letrozole (LETRO) and exemestane (EXE) respectively. CYP2A6 metaboliser status (MS) (poor, intermediate or normal) was determined based on alleles function (*1, *9, *2) and number of CYP2A6 copies. Trough plasma concentrations of each drug were determined 6 months after the start of the study by UPLC-MS/MS and were available for 342, 463 and 130 patients of the ANA, LETRO and EXE arms. Patients with AI concentrations below the limit of quantification were excluded for non-compliance (9 patients for ANA, 8 patients for LETRO and 7 patients for EXE). Toxicity was measured as a binary outcome (occurrence or worsening of hot flushes, fatigue, pain, arthralgia, vaginal dryness). All genetic associations were adjusted for multiple testing.

Results: ANA concentration was significantly higher in patients experiencing pain (p=0.025) and was associated with rs28365063 (UGT2B7 g.372A>G).

LETRO concentrations were strongly associated with CYP2A6 metabolizer status (p=0.0001) but did not differ in patients with or without toxicity.

In the EXE arm, patients with hot flushes or arthralgia had a significantly lower level of exemestane (p= 0.0002 and p=0.023 respectively) but since the metabolism of EXE leads to active 17-hydroexemestane, we can hypothesize that the lower EXE concentration is an indirect reflection of the metabolite formation. A SNP (rs2307424) in NR1I3 gene (coding for the constitutive androstane receptor CAR) was associated with EXE concentrations. CAR has been shown to regulate CYP2B6, which is involved in the formation of 6-hydroxy-methyl-exemestane (inactive metabolite).

Regarding the relationships between PG and toxicity, in the ANA arm, 3 SNPs of CYP19A1 gene tended to be associated with hot flushes worsening (rs934635) and arthralgia (rs10046 and rs2304463) but did not remain significant after multiple tests correction. In the EXE arm, several SNPs in NR1I3 gene were associated with fatigue.

In the LETRO arm, patients with a poor CYP2A6 MS had a higher risk of experiencing depression.

Conclusions: Our study confirms the predominant role of CYP2A6 in LETRO PK. To our knowledge, this is the first study to report on the role of UGT2B7 rs28365063 in ANA and NR1I3 in EXE PK and side effects. These relationships need to be re-evaluated with the drug concentrations obtained during the 3-year follow-up.

Citation Format: Thomas F, Marquet P, Pinguet F, White-Koning M, Robert J, Tafzi N, Solassol I, Despax R, Levasseur N, Ellis S, Massoubre A, Mbatchi L, Le Morvan V, Roché H, Chatelut E, Evrard A. Pharmacogenetic determinants of aromatase inhibitors pharmacokinetics and side effects: 6-month results of the adjuvant breast cancer longitudinal PHACS study (NCT01127295) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-12-07.

[Oxytocin administration during spontaneous labour: Guidelines for clinical practice. Guidelines short text]

OBJECTIVES

To define the different stages of spontaneous labour. To determine the indications, modalities of use and the effects of administering synthetic oxytocin. And to describe undesirable maternal and perinatal outcomes associated with the use of synthetic oxytocin.

METHOD

A systematic review was carried out by searching Medline database and websites of obstetrics learned societies until March 2016.

RESULTS

The 1st stage of labor is divided in a latence phase and an active phase, which switch at 5cm of cervical dilatation. Rate of cervical dilatation is considered as abnormal below 1cm per 4hour during the first part of the active phase, and below 1cm per 2hours above 7cm of dilatation. During the latent phase of the first stage of labor, i.e. before 5cm of cervical dilatation, it is recommended that an amniotomy not be performed routinely and not to use oxytocin systematically. It is not recommended to expect the active phase of labor to start the epidural analgesia if patient requires it. If early epidural analgesia was performed, the administration of oxytocin must not be systematic. If dystocia during the active phase, an amniotomy is recommended in first-line treatment. In the absence of an improvement within an hour, oxytocin should be administrated. However, in the case of an extension of the second stage beyond 2hours, it is recommended to administer oxytocin to correct a lack of progress of the presentation. If dynamic dystocia, it is recommended to start initial doses of oxytocin at 2mUI/min, to respect at least 30min intervals between increases in oxytocin doses delivered, and to increase oxytocin doses by 2mUI/min intervals without surpassing a maximum IV flow rate of 20mUI/min. The reported maternal adverse effects concern uterine hyperstimulation, uterine rupture and post-partum haemorrhage, and those of neonatal adverse effects concern foetal heart rate anomalies associated with uterine hyperstimulation, neonatal morbidity and mortality, neonatal jaundice, weak suck/poor breastfeeding latch and autism.

CONCLUSION

The widespread use of oxytocin during spontaneous labour must not be considered as simply another inoffensive prescription without any possible deleterious consequences for mother or foetus. Conditions for administering the oxytocin must therefore respect medical protocols. Indications and patient consent have to be report in the medical file.

[Parental perception of their involvement in the care of their children in French neonatal units]

BACKGROUND

The experience of becoming the parent of a sick or premature newborn can be particularly distressing for parents. They often encounter challenges to the development of their parenting roles. Perception of the hospital stay has never been analyzed on a large scale.

OBJECTIVE

To analyze parents' perception of their involvement in the care of their newborn.

METHODS

An internet-based survey started in France in February 2014 on the basis of a validated questionnaire composed of 222 neonatal care-related items. A quantitative and qualitative analysis was performed on the items dealing with parents' involvement until August 2014.

RESULTS

The survey was completed by 1500 parents, 98 % of whom were mothers. The infants had a mean GA of 32 weeks and a mean birth weight of 1600g. Parents rated their first care of their infant with mixed emotions (joy, stress, etc.). Parents were willing to practice new skills through guided participation, even for more complex care. Skin-to-skin care was only proposed after 7 days for 20 % of the parents; 10 % of the parents did not feel secure during this practice. The need for privacy and professional guidance was essential for meaningful skin-to-skin contact.

DISCUSSION

Parents' perception of participating actively in their infant's care was positive and they felt guided by the nursing team. Most of them would have been more active with guidance. Skin-to-skin care was appreciated and desired, but could become stressful if the conditions were not optimal.

A novel protein kinase involved in Na(+) exclusion revealed from positional cloning

Salinity is a major abiotic stress which affects crop plants around the world, resulting in substantial loss of yield and millions of dollars of lost revenue. High levels of Na(+) in shoot tissue have many adverse effects and, crucially, yield in cereals is commonly inversely proportional to the extent of shoot Na(+) accumulation. We therefore need to identify genes, resistant plant cultivars and cellular processes that are involved in salinity tolerance, with the goal of introducing these factors into commercially available crops. Through the use of an Arabidopsis thaliana mapping population, we have identified a highly significant quantitative trait locus (QTL) linked to Na(+) exclusion. Fine mapping of this QTL identified a protein kinase (AtCIPK16), related to AtSOS2, that was significantly up-regulated under salt stress. Greater Na(+) exclusion was associated with significantly higher root expression of AtCIPK16, which is due to differences in the gene's promoter. Constitutive overexpression of the gene in Arabidopsis leads to plants with significant reduction in shoot Na(+) and greater salinity tolerance. amiRNA knock-downs of AtCIPK16 in Arabidopsis show a negative correlation between the expression levels of the gene and the amount of shoot Na(+) . Transgenic barley lines overexpressing AtCIPK16 show increased salinity tolerance.

Calcium rubies: a family of red-emitting functionalizable indicators suitable for two-photon Ca2+ imaging

We designed Calcium Rubies, a family of functionalizable BAPTA-based red-fluorescent calcium (Ca(2+)) indicators as new tools for biological Ca(2+) imaging. The specificity of this Ca(2+)-indicator family is its side arm, attached on the ethylene glycol bridge that allows coupling the indicator to various groups while leaving open the possibility of aromatic substitutions on the BAPTA core for tuning the Ca(2+)-binding affinity. Using this possibility we now synthesize and characterize three different CaRubies with affinities between 3 and 22 μM. Their long excitation and emission wavelengths (peaks at 586/604 nm) allow their use in otherwise challenging multicolor experiments, e.g., when combining Ca(2+) uncaging or optogenetic stimulation with Ca(2+) imaging in cells expressing fluorescent proteins. We illustrate this capacity by the detection of Ca(2+) transients evoked by blue light in cultured astrocytes expressing CatCh, a light-sensitive Ca(2+)-translocating channelrhodopsin linked to yellow fluorescent protein. Using time-correlated single-photon counting, we measured fluorescence lifetimes for all CaRubies and demonstrate a 10-fold increase in the average lifetime upon Ca(2+) chelation. Since only the fluorescence quantum yield but not the absorbance of the CaRubies is Ca(2+)-dependent, calibrated two-photon fluorescence excitation measurements of absolute Ca(2+) concentrations are feasible.

Efficient large core fiber-based detection for multi-channel two-photon fluorescence microscopy and spectral unmixing

Low-magnification high-numerical aperture objectives maximize the collection efficiency for scattered two-photon excited fluorescence (2PEF), but non-descanned detection schemes for such objectives demand optical components much bigger than standard microscope optics. Fiber coupling offers the possibility of removing bulky multi-channel detectors from the collection site, but coupling and transmission losses are generally believed to outweigh the benefits of optical fibers. We present here two new developments based on large-core fiber-optic fluorescence detection that illustrate clear advantages over conventional air-coupled 2PEF detection schemes. First, with minimal modifications of a commercial microscope, we efficiently couple the output of a 20×/NA0.95 objective to a large-core liquid light guide and we obtain a 7-fold collection gain when imaging astrocytes at 100 μm depth in acute brain slices of adult ALDH1L1-GFP mice. Second, combining 2PEF microscopy and 4-color detection on a custom microscope, mode scrambling inside a 2-mm plastic optical fiber is shown to cancel out the spatially non-uniform spectral sensitivity observed with air-coupled detectors. Spectral unmixing of images of brainbow mice taken with a fiber-coupled detector revealed a uniform color distribution of hippocampal neurons across a large field of view. Thus, fiber coupling improves both the efficiency and the homogeneity of 2PEF collection.

[Early prenatal interview: implementation of a sheet link "carried" by patient. The Aurore perinatal network experience]

INTRODUCTION

Early prenatal interview has needed the implementation of a new communication tool between follow-up pregnancy professionals: a link sheet filled and carried by patients.

OBJECTIVE

To assess the utilization of link sheet by trained professionals, the contribution of the interview and the patient acceptation of the link sheet.

MATERIALS AND METHOD

Descriptive survey from the database of link sheets returned by professionals to Aurore perinatal network and semi-guided interviews with 100 randomized patients.

RESULT

One thousand one hundred and nineteen link sheets were sent to Aurore perinatal network by 55 professionals out of 78 trained. For primipare, precocious prenatal interview contribution has concerned health care security (60%) and emotional security (56%). For multipare, this contribution has concerned mainly emotional security (80%). No interviewed patient has refused link sheet principle.

CONCLUSION

Link sheet principle, like implemented by Aurore perinatal network, seems pertinent to professionals and patients but it constitutes only one of the elements of network elaboration of personalized care.

Abnormal response of dopaminergic neurons to nicotine without perturbation of nicotinic receptors in alphaCGRP knock-out mice

Alpha-calcitonin gene-related peptide (alphaCGRP) is a neuropeptide with multiple biological properties, including the regulation of nicotinic acetylcholine receptors (nAChRs). We have previously reported a reduction of somatic withdrawal symptoms in alphaCGRP knock-out mice exposed to chronic nicotine, leading us to investigate the contribution of alphaCGRP to the regulations of ventral tegmental area (VTA) neurons and their response to nicotine. The electrophysiological activity of VTA dopaminergic (DA) neurons was recorded in vivo, under anesthesia. These neurons displayed identical spontaneous electrophysiogical activities in wild-type and alphaCGRP-/- mice. However, we found that intravenous administration of nicotine (30 microg/kg) had no significant effect on the activity of DA neurons in alphaCGRP-/- mice, whereas it induced a doubling of the firing rate in wild-type animals. A higher dose (90 microg/kg) produced a significant excitation in both strains, but this effect remained smaller in the mutants. To investigate this difference, we have studied the functional state of nAChRs in wild-type and alphaCGRP-/- mice. Both strains exhibited identical expression of alpha(7) and alpha(4)beta(2) nAChRs as revealed by autoradiographical studies in the VTA. In addition, focal application of acetylcholine on DA neurons recorded by patch-clamp revealed identical currents mediated by nAChRs in mutant animals, as compared to wild-type mice. These data outline the possibility of a contribution of alphaCGRP to the effects of nicotine on DA neurons, by a physiological pathway independent of VTA nicotinic receptors.

Familial partial lipodystrophy due to the LMNA R482W mutation with multinodular goitre, extrapyramidal syndrome and primary hyperaldosteronism

Objective To describe new data about the wide phenotypic variability of diseases due to mutations in the lamin A/C gene (LMNA). Design We report a complex phenotype in a patient with familial partial lipodystrophy of the Dunnigan type (FPLD) and study the frequency of her unusual clinical signs in 19 other LMNA-mutated lipodystrophic patients from 8 different families and 14 non-mutated family members. Case Report The patient was diagnosed with FPLD due to the R482W LMNA mutation after familial screening. Surprisingly, she had no biological signs of insulin resistance. The presence of hypertension with hypokalaemia led to the diagnosis of primary hyperaldosteronism. Thyroid investigations showed a euthyroid multinodular goiter. In addition, the patient exhibited a juvenile akineto-hypertonic syndrome. Results Goiter was identified with a similar frequency (55%) in LMNA-mutated lipodystrophic patients (11 out of 20, originating from 5 families among 8) compared to non-mutated family controls (35%; 5 patients out of 14, all originating from the same family). No case of primary hyperaldosteronism or extrapyramidal syndrome was identified in other studied subjects, either LMNA-mutated or not. Conclusions This R482W-LMNA mutated patient showed an association of features (primary hyperaldosteronism, euthyroid goiter and extra-pyramidal syndrome, raising the question of a link with her laminopathy. Prevalence of goiter tended to be higher in LMNA-mutated than in non-mutated subjects. Hyperaldosteronism seems coincidental. Although extrapyramidal syndrome has never been reported in lipodystrophic patients, it may nevertheless be linked to the LMNA mutation since multiple neurological features have been associated with alterations in lamins A/C.

Targeted in vivo expression of nicotinic acetylcholine receptors in mouse brain using lentiviral expression vectors

Nicotinic acetylcholine receptors (nAChRs) in the brain exhibit diverse functional properties and ubiquitous distribution. Yet, except for providing a receptor for the exogenously applied nicotine of tobacco products, their role in the normal functioning of the brain has remained elusive. We have used a lentiviral expression vector to re-express the beta2 subunit specifically in the ventral tegmental area (VTA) of beta2-/- mice. The viral vector efficiently expresses beta2- subunit protein leading to new nAChR-binding sites. VTA neurons transduced by the lentiviral vector are responsive to intravenous nicotine when analyzed using in vivo electrophysiology. Nicotine-induced dopamine release from the nucleus accumbens (NuAcc) was also restored in re-expressing beta2-/- mice. Intra-VTA injection of nicotine was found to be reinforcing in both wild-type and beta2-subunit re-expressing beta2-/- mice, but not in beta2-/- mice. Furthermore, in the absence of applied nicotine, the spontaneous slow exploratory behavior of the mice was restored, whereas fast navigation did not change. This latter behavioral analysis suggests a role for beta2* nAChR, specifically expressed in the VTA, in mammalian cognitive function.

Hierarchical control of dopamine neuron-firing patterns by nicotinic receptors

Nicotine elicits dopamine release by stimulating nicotinic acetylcholine receptors (nAChRs) on dopaminergic neurons. However, a modulation of these neurons by endogenous acetylcholine has not been described. We recorded, in vivo, the spontaneous activity of dopaminergic neurons in the VTA of anaesthetized wt and nAChR knockout mice and their response to nicotine injections. Deleting alpha7 or beta2 subunits modified the spontaneous firing patterns, demonstrating their direct stimulation by endogenous acetylcholine. Quantitative analysis further revealed four principal modes of firing, each depending on the expression of particular nAChR subunits and presenting unique responses to nicotine. The prominent role of the beta2 subunit was further confirmed by its selective lentiviral reexpression in the VTA. These data suggest a hierarchical control of dopaminergic neuron firing patterns by nAChRs: activation of beta2*-nAChR switches cells from a resting to an excited state, whereas activation of alpha7*-nAChRs finely tunes the latter state but only once beta2*-nAChRs have been activated.

Determination of uracil/UH2 ratio as a potential surrogate for DPD status in cancer patients presenting with severe toxicities during fluoropyrimidine treatment

2020

Background: DPD deficiency is a rare pharmacogenetic syndrome leading to overexposure to fluoropyrimidine drugs, with subsequent exacerbation of toxicity and, possibly, fatal outcome in the most severe cases. Methods: We developed a simple and rapid surrogate method for evaluating the DPD status of cancer patients. This method was retrospectively validated by following 860 patients treated with fluoropyrimidines over a 3-year period at our institute. We applied the Uracil to UH2 ratio measurement as an indirect insight into DPD functionality in a subset of 120 patients (14%), who had presented with severe toxicity (grade 3–5, WHO) after fluoropyrimidine administration. We also searched for the canonical IVS14+1G>A single nucelotide permutation (SNP), which is associated with severe DPD deficiency. Results: More than 70% of the patients with severe toxicity and 80% of those with fatal outcome displayed U/UH2 ratios out of the range previously defined with a separate reference, non-toxic population thus strongly suggesting a correlation. In contrast, IVS14+1G>A SNP was not found to be a reliable marker for predicting toxicities. Conclusions: Taken together, our data indicate U/UH2 ratio appears to be frequently implicated in the occurrence of iatrogenic events with fluoropyrimidine therapy. In addition, our simple and rapid HPLC method may meet the requirements of routine screening, allowing identification of patients who might be at risk of severe toxicity during fluoropyrimidine administration, at relatively low cost. The predictive value of our test is being investigated in a prospective study with pharmacokinetic support.

No significant financial relationships to disclose.

Glucocorticoid Receptor-Dependent Desensitization of 5-HT1A Autoreceptors by Sleep Deprivation: Studies in GR-i Transgenic Mice

Sleep deprivation for one night induces mood improvement in depressed patients, an action that probably involves the serotonergic (5-HT) system. In animals, sleep deprivation and pharmacologic treatment with antidepressants exert similar effects on 5-HT neurotransmission, notably functional desensitization of 5-HT1A autoreceptors located on 5-HT neurons in the dorsal raphe nucleus (DRN). However, in stressful conditions, corticosterone can also induce a desensitization of these autoreceptors.

STUDY OBJECTIVES

To investigate the mechanisms of this adaptation during sleep deprivation and the possible involvement of corticosterone, we studied the effects of an 18-hour sleep deprivation, by forced locomotion, on 5-HT1A receptor-mediated firing response of DRN 5-HT neurons in transgenic mice with impaired glucocorticoid-receptor expression (GR-i) and in wild-type animals. We also examined the effects of chronic treatment with the antidepressant drug fluoxetine in the same paradigm.

MEASUREMENTS AND RESULTS

In both wild-type and GR-i mice, the 18-hour sleep deprivation or fluoxetine treatment had no effect on the spontaneous firing of 5-HT neurons recorded under anesthesia. However, sleep deprivation decreased the potency of the 5-HT1A agonist 8-OH-DPAT to inhibit 5-HT neuronal firing in wild-type mice, whereas it had no effect in GR-i animals. Conversely, after chronic fluoxetine treatment, the induced reduction of this 5-HT1A autoreceptor-driven response was of larger amplitude in GR-i than in wild-type mice.

CONCLUSIONS

These data suggest that glucocorticoid-receptor activation by corticosterone participates in the antidepressant-like adaptive changes in 5-HT1A autoreceptors in sleep-deprived mice. On the other hand, GR-i animals exhibited enhanced 5-HT1A autoreceptor desensitization induced by fluoxetine, in line with data in other animal models of depression.

Combined effects of GSTP1 and MRP1 in melanoma drug resistance

Glutathione-S-transferase Pi1 (GSTP1) and multidrug resistance protein 1 (MRP1) are overexpressed in melanoma, a skin cancer notoriously resistant to all current modalities of cancer therapy. To investigate the involvement of these detoxifying enzymes in the drug resistance of melanoma, an inducible (Tet-On™ system) antisense (AS) RNA strategy was used to specifically inhibit GSTP1 expression in A375 cells, a human melanoma cell line expressing high levels of GSTP1 and MRP1. Stable transfectant clones were established and analysed for GSTP1 inhibition by AS RNA. The clone A375-ASPi1, presenting a specific 40% inhibition of GSTP1 expression in the presence of doxycycline, was selected. Lowering the GSTP1 level significantly increased (about 3.3-fold) the sensitivity of A375-ASPi1 cells to etoposide. Inhibitors of glutathione synthesis (BSO), GSTs (curcumin, ethacrynic acid), and also of MRPs (MK571, sulphinpyrazone) improved the sensitising effect of GSTP1 AS RNA. All these inhibitors had stronger sensitising effects in control cells expressing high GSTP1 level (A375-ASPi1 cells in the absence of doxycycline). In conclusion, GSTP1 can act in a combined fashion with MRP1 to protect melanoma cells from toxic effects of etoposide.

Nicotine reinforcement and cognition restored by targeted expression of nicotinic receptors

Worldwide, 100 million people are expected to die this century from the consequences of nicotine addiction, but nicotine is also known to enhance cognitive performance. Identifying the molecular mechanisms involved in nicotine reinforcement and cognition is a priority and requires the development of new in vivo experimental paradigms. The ventral tegmental area (VTA) of the midbrain is thought to mediate the reinforcement properties of many drugs of abuse. Here we specifically re-expressed the beta2-subunit of the nicotinic acetylcholine receptor (nAChR) by stereotaxically injecting a lentiviral vector into the VTA of mice carrying beta2-subunit deletions. We demonstrate the efficient re-expression of electrophysiologically responsive, ligand-binding nicotinic acetylcholine receptors in dopamine-containing neurons of the VTA, together with the recovery of nicotine-elicited dopamine release and nicotine self-administration. We also quantified exploratory behaviours of the mice, and showed that beta2-subunit re-expression restored slow exploratory behaviour (a measure of cognitive function) to wild-type levels, but did not affect fast navigation behaviour. We thus demonstrate the sufficient role of the VTA in both nicotine reinforcement and endogenous cholinergic regulation of cognitive functions.

Reduction of withdrawal signs after chronic nicotine exposure of alpha-calcitonin gene-related peptide knock-out mice

Nicotine, the main substance responsible for the addictive behavior of smokers, binds to a variety of nicotinic acetylcholine receptors (nAChRs) diversely distributed in the brain, notably in areas involved in motivation and reward mechanisms. The alpha-calcitonin gene-related peptide (alphaCGRP) has been previously shown to modulate the functions of nAChRs and is released in brain areas implicated in motivation, such as the amygdala or the ventral tegmental area. Interestingly, alphaCGRP -/- mice display a decrease in morphine withdrawal symptoms. In this context, we investigate the tolerance and withdrawal symptoms in alphaCGRP -/- mice exposed to acute and chronic nicotine. We report that these animals develop a normal tolerance to the antinociceptive effects of nicotine, but display an attenuation of somatic withdrawal symptoms.

Sex hormone-dependent desensitization of 5-HT1A autoreceptors in knockout mice deficient in the 5-HT transporter

The serotonin transporter (5-HTT) is the target of most antidepressant drugs, whose therapeutic action is related to their facilitatory influence on 5-HT neurotransmission. In this study, we investigated the functional adaptive properties of 5-HT1A autoreceptors, which regulate serotonergic neuronal firing, in knockout mice deficient in 5-HTT. Neurons of the dorsal raphe nucleus (DRN) were recorded extracellularly under chloral hydrate anaesthesia in male and female knockout 5-HTT mice and their wild-type counterparts. The inhibitory response of DRN neurons to intravenous injection of the 5-HT1A agonist 8-OH-DPAT was dramatically reduced in knockout 5-HTT compared with wild-type mice, especially in females. Changes in 8-OH-DPAT-induced hypothermia and autoradiographic labelling of 5-HT1A sites in the DRN confirmed a greater level of desensitization/down-regulation of 5-HT1A autoreceptors in female than in male knockout 5-HTT mice. After gonadectomy, the functional status of 5-HT1A autoreceptors was unchanged in wild-type mice, whereas in knockout 5-HTT, castrated males exhibited a down-regulation, and ovariectomized females an up-regulation of these receptors, as shown by electrophysiological recording and autoradiographic labelling in the DRN, as well as by changes in 8-OH-DPAT-induced hypothermia. Finally, in gonadectomized knockout 5-HTT mice, treatment with testosterone or estradiol restored the DRN neuronal firing sensitivity to 8-OH-DPAT back to sham control level in males or females, respectively. These data indicate that sexual hormones participate in the mechanisms responsible for the desensitization of 5-HT1A autoreceptors in knockout 5-HTT mice. The differential effects of testosterone and estradiol on 5-HT1A-mediated control of 5-HT neurotransmission might be related to the well-established gender differences in the vulnerability to depression.

Altered regulation of the 5-HT system in the brain of MAO-A knock-out mice

Genetic deficiency of monoamine oxidase-A (MAO-A) induces major alterations of mood and behaviour in human. Because serotonin (5-HT) is involved in mood regulation, and MAO-A is responsible for the catabolism of 5-HT, we investigated 5-HT mechanisms in knock-out mice (2-month-old) lacking MAO-A, using microdialysis, electrophysiological, autoradiographic and molecular biology approaches. Compared to paired wild-type mice, basal extracellular 5-HT levels were increased in ventral hippocampus (+202%), frontal cortex (+96%) and dorsal raphe nucleus (DRN, +147%) of MAO-A mutant mice. Conversely, spontaneous firing rate of 5-HT neurons in the DRN (recorded under chloral hydrate anaesthesia) was approximately 40% lower in mutants. Acute 5-HT reuptake blockade by citalopram (0.2 and 0.8 mg/kg i.v.) produced a much larger increase in extracellular 5-HT levels (by approximately 4 fold) and decrease in DRN neuronal firing (with a approximately 4.5 fold decrease in the drug's ED50) in MAO-A knock-out mice, which expressed lower levels of the 5-HT transporter throughout the brain (-13 to -34% compared to wild-type levels). The potency of the 5-HT1A agonist 8-OH-DPAT to produce hypothermia and to reduce the firing of DRN serotoninergic neurons was significantly less in the mutants, indicating a desensitization of 5-HT1A autoreceptors. This was associated with a decreased autoradiographic labelling of these receptors (-27%) in the DRN. Altogether, these data indicate that, in MAO-A knock-out mice, the enhancement of extracellular 5-HT levels induces a down-regulation of the 5-HT transporter, and a desensitization of 5-HT1A autoreceptors which allows the maintenance of tonic activity of 5-HT neurons in the DRN.

Combination of thymidine phosphorylase gene transfer and deoxyinosine treatment greatly enhances 5-fluorouracil antitumor activity in vitro and in vivo

We reported previously that 5-fluorouracil (FUra) efficacy could be enhanced by increasing tumoral thymidine phosphorylase (TP) activity. Potentiated TP yield was achieved by either transfecting cells with human TP gene (A. Evrard et al., Br. J. Cancer, 80: 1726-1733, 1999) or associating FUra with 2'-deoxyinosine (d-Ino), a modulator providing the tumors with TP cofactor deoxyribose 1-phosphate (J. Ciccolini et al., Clin. Cancer Res., 6: 1529-1535, 2000). The purpose of the present work was to study the effects of a combined modulation (TP gene transfer + use of d-Ino) on the sensitivity to FUra of the LS174T human colorectal cell line. Results showed a near 4000 times increase of cell sensitivity in vitro after double (genetic + biochemical) modulation. This potentiation of tumor response was accompanied by a total change in the FUra anabolic pathway with a 5000% increase of cytosolic fluorodeoxyuridine monophosphate, a stronger and longer inhibition of thymidylate synthase, and 300% augmentation of DNA damage. Besides, whereas thymidine failed to inhibit FUra cytotoxicity in LS174T wild-type cells, the potentiation of the antitumor activity observed in the modulating regimen was partly reversed by thymidine, indicative of thymidylate synthase as the main drug target. The impact of this double modulation was next investigated in xenograft-bearing nude mice. Results showed that whereas FUra alone was completely ineffective on wild-type tumor growth, the size of TP-transfected tumors in animals treated with the FUra/d-Ino combination was reduced by 80% (P < 0.05). Our results suggest that FUra exhibits stronger antiproliferative activity when activated via TP through the DNA pathway and that high tumoral TP activity therefore leads to enhanced sensitivity to fluoropyrimidines.

Fluoropyrimidine sensitivity of human MCF-7 breast cancer cells stably transfected with human uridine phosphorylase

The relationship between uridine phosphorylase (UP) expression level in cancer cells and the tumour sensitivity to fluoropyrimidines is unclear. In this study, we found that UP overexpression by gene transfer, and the subsequent efficient metabolic activation of 5-fluorouracil (5-FU) by the ribonucleotide pathway, does not increase the fluoropyrimidine sensitivity of MCF-7 human cancer cells.

Regulation of protein degradation and protease expression by mannose in maize root tips. Pi sequestration by mannose may hinder the study of its signaling properties

The effects of mannose (Man) and glucose (Glc) on central metabolism, proteolysis, and expression of the root starvation-induced protease (RSIP; F. James, R. Brouquisse, C. Suire, A. Pradet, P. Raymond [1996] Biochem J 320: 283-292) were investigated in maize (Zea mays L. cv DEA) root tips. Changes in metabolite concentrations (sugars, ester-phosphates, adenine nucleotides, and amino acids) were monitored using in vivo and in vitro (13)C- and (31)P-NMR spectroscopy, in parallel with the changes in respiration rates, protein contents, proteolytic activities, and RSIP amounts. The inhibition of proteolysis, the decrease in proteolytic activities, and the repression of RSIP expression triggered by Man, at concentrations usually used to study sugar signaling (2 and 10 mM), were found to be related to a drop of energy metabolism, primarily due to a Man-induced Pi sequestration. However, when supplied at low concentration (2 mM) and with the adequate phosphate concentration (30 mM), energy metabolism was restored and Man repressed proteolysis similarly to Glc, when provided at the same concentration. These results indicate that Man should be used with caution as a Glc analog to study signalization by sugars in plants because possible signaling effects may be hindered by Pi sequestration.

Altered expression and functions of serotonin 5-HT1A and 5-HT1B receptors in knock-out mice lacking the 5-HT transporter

By taking up serotonin (5-hydroxytryptamine, 5-HT) released in the extracellular space, the 5-HT transporter (5-HTT) regulates central 5-HT neurotransmission. Possible adaptive changes in 5-HT neurotransmission in knock-out mice that do not express the 5-HT transporter were investigated with special focus on 5-HT1A and 5-HT1B receptors. Specific labelling with radioligands and antibodies, and competitive RT-PCR, showed that 5-HT1A receptor protein and mRNA levels were significantly decreased in the dorsal raphe nucleus (DRN), increased in the hippocampus and unchanged in other forebrain areas of 5-HTT-/- vs. 5-HTT+/+ mice. Such regional differences also concerned 5-HT1B receptors because a decrease in their density was found in the substantia nigra (-30%) but not the globus pallidus of mutant mice. Intermediate changes were noted in 5-HTT+/- mice compared with 5-HTT+/+ and 5-HTT-/- animals. Quantification of [35S]GTP-gamma-S binding evoked by potent 5-HT1 receptor agonists confirmed such changes as a decrease in this parameter was noted in the DRN (-66%) and the substantia nigra (-30%) but not other brain areas in 5-HTT-/- vs. 5-HTT+/+ mice. As expected from actions mediated by functional 5-HT1A and 5-HT1B autoreceptors, a decrease in brain 5-HT turnover rate after i.p. administration of ipsapirone (a 5-HT1A agonist), and an increased 5-HT outflow in the substantia nigra upon local application of GR 127935 (a 5-HT1B/1D antagonist) were observed in 5-HTT+/+ mice. Such effects were not detected in 5-HTT-/- mice, further confirming the occurrence of marked alterations of 5-HT1A and 5-HT1B autoreceptors in these animals.

Enhanced antitumor activity of 5-fluorouracil in combination with 2'-deoxyinosine in human colorectal cell lines and human colon tumor xenografts

We investigated the effects of 2'-deoxyinosine (d-Ino), a modulator yielding thymidine phosphorylase activity, on cellular pharmacology of 5-fluorouracil (FUra) in various human colorectal cell lines and its antitumoral activity when combined with FUra in human xenografts. Associating d-Ino with FUra increased by 38 up to 700 times the sensitivity of HT29 and FUra-resistant SW620 lines, respectively, but not of CaCO2 cells, although high levels of intracellular FdUMP and subsequent higher thymidylate synthase inhibition were observed. Cell death studies confirmed the ability of d-Ino to enhance both early and late apoptosis induced by FUra in HT29 and SW620 but not in CaCo2. Similarly, we showed that associating d-Ino increased by 68 up to 101% the Fas overexpression induced by FUra in HT29 and SW620 but not in CaCo2 cells. Anti-Fas and anti-FasL antibodies both partly reversed this increase of cell sensitivity, thus confirming the role Fas plays in the modulation of FUra toxicity by d-Ino. This Fas component could explain the discrepancy between the lines because CaCO2 has been described as insensitive to Fas-mediated apoptosis. Antitumor activity of the combination was next investigated in nude mice transplanted with SW620. Results showed that although FUra alone has little effect on SW620 xenografts (P > 0.05), associating d-Ino significantly reduced the tumor growth by 57% (P < 0.05). This study suggests that it is possible to reduce both in vitro and in vivo resistance to FUra by modulating the way the drug is converted after cellular uptake.

[Nephrogenic diabetes insipidus]

Nephrogenic diabetes insipidus (NDI) is a rare disease characterized by polyuro-polydipsic syndrome (> 30 ml/kg/day in adult) related to an inability to concentrate the urine secondary to resistance to the antidiuretic action of vasopressin (AVP) or to its V2 agonist, dDAVP. NDI may be congenital or acquired. Congenital NDI, familial in most cases, are related in 90% of cases to mutations of the gene coding for V2 receptor of AVP (X-linked recessive disease), and in 10% of cases, to mutations of the gene encoding for aquaporin 2 (autosomic recessive disease). This water channel is expressed at the apical membrane of principal cells of collecting ducts and mediates water transport across the apical plasma membrane of these cells. It is regulated by AVP in two ways. First, AVP has a short term effect in triggering translocation of aquaporin-2-containing intracytoplasmic vesicles to the apical membrane. Second, AVP has a long term effect in increasing the expression of aquaporin-2 in collecting duct. Acquired NDI are iatrogenic (lithium), or related to electrolytic (hypokalemia) or renal abnormalities. The mechanism of these acquired NDI is a decrease of aquaporin 2 abundance in the renal collecting duct.

5-HT1A and 5-HT1B receptors control the firing of serotoninergic neurons in the dorsal raphe nucleus of the mouse: studies in 5-HT1B knock-out mice

The characteristics of the spontaneous firing of serotoninergic neurons in the dorsal raphe nucleus and its control by serotonin (5-hydroxytryptamine, 5-HT) receptors were investigated in wild-type and 5-HT1B knock-out (5-HT1B-/-) mice of the 129/Sv strain, anaesthetized with chloral hydrate. In both groups of mice, 5-HT neurons exhibited a regular activity with an identical firing rate of 0.5-4.5 spikes/s. Intravenous administration of the 5-HT reuptake inhibitor citalopram or the 5-HT1A agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) induced a dose-dependent inhibition of 5-HT neuronal firing which could be reversed by the selective 5-HT1A antagonist N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl)cyclohe xane carboxamide (WAY 100635). Both strains were equally sensitive to 8-OH-DPAT (ED50 approximately 6.3 microgram/kg i.v.), but the mutants were less sensitive than wild-type animals to citalopram (ED50 = 0.49 +/- 0.02 and 0.28 +/- 0.01 mg/kg i.v., respectively, P < 0.05). This difference could be reduced by pre-treatment of wild-type mice with the 5-HT1B/1D antagonist 2'-methyl-4'-(5-methyl-[1,2,4]oxadiazol-3-yl)-biphenyl-4-carbox yli c acid [4-methoxy-3-(4-methyl-piperazine-1-yl)-phenyl]amide (GR 127935), and might be accounted for by the lack of 5-HT1B receptors and a higher density of 5-HT reuptake sites (specifically labelled by [3H]citalopram) in 5-HT1B-/- mice. In wild-type but not 5-HT1B-/- mice, the 5-HT1B agonists 3-(1,2,5, 6-tetrahydro-4-pyridyl)-5-propoxypyrrolo[3,2-b]pyridine (CP 94253, 3 mg/kg i.v.) and 5-methoxy-3-(1,2,3, 6-tetrahydropyridin-4-yl)-1H-indole (RU 24969, 0.6 mg/kg i.v.) increased the firing rate of 5-HT neurons (+22.4 +/- 2.8% and +13.7 +/- 6.0%, respectively, P < 0.05), and this effect could be prevented by the 5-HT1B antagonist GR 127935 (1 mg/kg i.v.). Altogether, these data indicate that in the mouse, the firing of 5-HT neurons in the dorsal raphe nucleus is under both an inhibitory control through 5-HT1A receptors and an excitatory influence through 5-HT1B receptors.

Increased cytotoxicity and bystander effect of 5-fluorouracil and 5-deoxy-5-fluorouridine in human colorectal cancer cells transfected with thymidine phosphorylase

5-Fluorouracil (5-FU) and 5'-deoxy-5-fluorouridine (5'-DFUR), a prodrug of 5-FU, are anticancer agents activated by thymidine phosphorylase (TP). Transfecting the human TP cDNA into cancer cells in order to sensitize them to these pyrimidine antimetabolites may be an important approach in human cancer gene therapy research. In this study, an expression vector containing the human TP cDNA (pcTP5) was transfected into LS174T human colon carcinoma cells. Eight stable transfectants were randomly selected and analysed. The cytotoxic effects of 5-FU and 5'-DFUR were higher in TP-transfected cells as compared to wild-type cells. The maximal decreases in the IC50 were 80-fold for 5-FU and 40-fold for 5'-DFUR. The increase in sensitivity to these pyrimidines of TP-transfected cells significantly correlated with the increase in both TP activity and TP expression. Transfected clone LS174T-c2 but not wild-type cells exhibited formation of [3H]FdUMP from [3H]5-FU. In addition the LS174T-c2 clone enhanced the cytotoxic effect of 5'-DFUR, but also that of 5-FU, towards co-cultured parental cells. For both anti-cancer agents, this bystander effect did not require cell-cell contact. These results show that both 5-FU or 5'-DFUR could be used together with a TP-suicide vector in cancer gene therapy.

[Relationship between corticotropin and arginine vasopressin in endocrine diseases]

VASOPRESSIN: The action of vasopressin (AVP) is not limited to regulating water excretion but also plays an essential role in regulating the corticotropic axis during stress. PHYSIOLOGY: Vasopressin is synthesized in the hypothalamus and stored in the posterior pituitary. It acts on 3 types of receptors (RV). RV1a are vascular receptors mediating the vasoconstrictor and glycogenolytic effects of the hormone. Anterior pituitary RV1b or V3 mediate stimulating effects on the corticotropic axis. Renal RV2 regulate water and urea excretion. Hypothetical extrarenal RV2 would be responsible for the vasodilator and procoagulant effects of the hormone. MODIFICATIONS IN ENDOCRINE DISEASES: Pituitary or adrenal hypocorticism syndromes include hyponatremia with secondary plasma hypoosmolality and reduced glomerular filtration due to the direct effect of glucocorticoids and also the effect of vasopressinism. Certain endogenous hypercorticisms appear to be related to an overexpression of RV: in ACTH-independent Cushingís syndrome, adrenal overexpression of eutopic RV1a, and in ACTH-dependent Cushingís syndrome, pituitary overexpression of eutopic RV1b or ectopic RV2. In addition, inappropriate secretion of antidiuretic hormone is frequent after transphenoidal surgery, particularly for corticotropic adenomas. DYNAMIC TESTS: The physiological response of ACTH and also AVP to corticotropin releasing hormone (CRH) in the petrous sinus, the unusual responses of certain corticotropic tumors to dDAVP, or certain forms of ACTH-independent hypercortisolism to lysine vasopressin (LVP) suggest excessive or ectopic expression of RV in corticotropic or adrenal cells: tumorgenesis of these cells could also depend, at least partially, on AVP.

31P nuclear magnetic resonance study of the flavoprotein component of the Escherichia coli sulfite reductase

SiR-FP60, the monomeric form of the Escherichia coli sulfite reductase flavoprotein component (SiR-FP), has been analysed by 31P-NMR spectroscopy. This protein was reported previously as a reliable simplified model for native SiR-FP [Zeghouf, M., Fontecave, M., Macherel, D., & Covès, J. (1998) Biochemistry 37, 6117-6123]. SiR-FP60 was examined in its native form, as a complex with NADP+ and after monoelectronic reduction either with NADPH or dithionite. In these latter cases, the stabilized FMN semiquinone radical offers a natural and internal paramagnetic probe. The paramagnetic effect of added manganese was also studied. In each case, the NMR parameters were extracted from digitalized data by a deconvolution procedure and compared with those obtained previously with cytochrome P450 reductase. Evolution of the NMR parameters and of calculated relaxation rate constants upon biochemical modifications of SiR-FP60 led us to propose that the reactive center is more compact than the one of cytochrome P450 reductase, with the redox components, FMN, FAD and NADPH, in a tighter spatial arrangement, close to the protein surface. This underlies some subtle differences between the two proteins for which a very similar overall structure is likely considering their common genetic origin and common operating cycle.

[Atrial natriuretic hormone and endocrine functions]

The atrial natriuretic hormone (ANP) is a cardiac hormone which gene and receptors are widely present in the body. Its main function is to lower blood pressure and to control electrolyte homeostasis. Its main targets are the kidney and the cardiovascular system but ANP interacts with many other hormones in order to regulate their secretion. The adrenal glands are the first endocrine target. Steroidogenesis, especially mineralocorticoid synthesis, is inhibited by ANP, but glucocorticoid production seems to be depressed too. As ANP synthesis is enhanced by the latter, it suggests a regulatory loop. Moreover ANP inhibits the thyroid synthesis whereas its production is enhanced by thyroid hormone. The hypothalamo-hypophyseal axis is another important target. ANP inhibits ACTH release and arginine vasopressin secretion. Vasopressin enhances ANP synthesis while GH decreases it. Finally the endocrine effects of ANP strengthen the cardiovascular and renal effects of the hormone, antagonizing the salt and water retention due to aldosterone and AVP. Because of a local production, ANP may also act as a paracrine hormone that influences the function of many endocrine systems (ovarian function for instance). In the central nervous system, ANP acts as a neurotransmitter in order to regulate pituitary and vegetative functions. Plasma ANP levels are impaired in several endocrine diseases : the plasma hormone levels increase in hypercortisolism, hyperaldosteronism, thyrotoxicosis and inappropriate antidiuretic hormone secretion; it decreases in hypothyroidism. In case of Addison's disease, ANP may be used to assess the quality of mineralocorticoid treatment, in association with the other biological criteria.

Enhancement of 5-fluorouracil cytotoxicity by human thymidine-phosphorylase expression in cancer cells: in vitro and in vivo study

Transferring a gene into cancer cells in order to sensitize them to drugs is an important approach in human cancer gene-therapy research. Thymidine phosphorylase (TP) is the first enzyme in the metabolic activation pathway of 5-fluorouracil (5-FU) to fluorodeoxyribonucleotides, thus, it could be used to increase the sensitivity of cancer cells to this anti-pyrimidine agent. In this study, an expression vector containing the human TP cDNA was transfected into C26 murine colon-carcinoma cells. Stable transfectants were selected; all showed increased TP activity, ranging from 2- to 10-fold when compared with wild-type cells. The in vitro sensitivity of transfectants to 5-FU and 5'-deoxy-5-fluorouridine (5'-DFUR) was enhanced, in agreement with the observed increase in TP activity. Then, tumors were generated by s.c. injection of TP-transfected or wild-type C26 cells in syngeneic BALB/c mice. 5-FU (25 mg/kg, i.p.) induced a growth delay of TP-transfected C26 tumors as compared with C26 wild-type tumors. These data suggest that TP could be transfected in tumor cells to increase the sensitivity to 5-FU for subsequent cancer gene therapy.

Transient pseudo-hypoaldosteronism following resection of the ileum: normal level of lymphocytic aldosterone receptors outside the acute phase

Pseudo-hypoaldosteronism (PHA) is due to mineralocorticoid resistance and manifests as hyponatremia and hyperkalemia with increased plasma aldosterone levels. It may be familial or secondary to abnormal renal sodium handling. We report the case of a 54-year-old woman with multifocal cancer of the colon, who developed PHA after subtotal colectomy, ileal resection and jejunostomy. She was treated with 6 g of salt daily to prevent dehydration, which she stopped herself because of reduced fecal losses. One month later she was admitted with signs of acute adrenal failure, i.e. fatigue, severe nausea, blood pressure of 80/60 mmHg, extracellular dehydration, hyponatremia (118 mmol/l); hyperkalemia (7.6 mmol/l), increased blood urea nitrogen (BUN) (200 mg/dl) and creatininemia (2.5 mg/dl), and decreased plasma bicarbonates level (HCO3-: 16 mmol/l; N: 27-30). However, the plasma cortisol was high (66 microg/100 ml at 10:00 h; N: 8-15) and the ACTH was normal (13 pg/ml, N: 10-60); there was a marked increase in plasma renin activity (>37 ng/ml/h; N supine <3), active renin (869 pg/ml; N supine: 1.120), aldosterone (>2000 pg/ml; N supine <150) and plasma AVP (20 pmol/l; N: 0.5-2.5). The plasma ANH level was 38 pmol/l (N supine: 5-25). A urinary steroidogram resulted in highly elevated tetrahydrocortisol (THF: 13.3 mg/24h; N: 1.4+/-0.8) with no increase in tetrahydrocortisone (THE: 3.16 mg/24h; N: 2.7+/-2.0) excretion, and with low THE/THF (0.24; N: 1.87+/-0.36) and alpha THF/THF (0.35; N: 0.92+/-0.42) ratios. The number of mineralocorticoid receptors in mononuclear leukocytes was in the lower normal range for age, while the number of glucocorticoid receptors was reduced. Small-bowel resection in ileostomized patients causes excessive fecal sodium losses and results in chronic sodium depletion with contraction of the plasma volume and severe secondary hyperaldosteronism. Nevertheless, this hyperaldosteronism may be associated with hyponatremia and hyperkalemia suggesting PHA related to the major importance of the colon for the absorption of sodium. In conclusion, this case report emphasizes 1) the possibility of a syndrome of acquired PHA with severe hyperkalemia after resection of the ileum and colon responding to oral salt supplementation; 2) the major increase in AVP and the small increase in ANH; 3) the strong increase in urinary THF with low THE/THF and alpha THF/THF ratios; 4) the normal number of lymphocytic mineralocorticoid receptors outside the acute episode.

Enhancement of 5-fluorouracil cytotoxicity by human thymidine-phosphorylase expression in cancer cells: in vitro and in vivo study

Transferring a gene into cancer cells in order to sensitize them to drugs is an important approach in human cancer gene-therapy research. Thymidine phosphorylase (TP) is the first enzyme in the metabolic activation pathway of 5-fluorouracil (5-FU) to fluorodeoxyribonucleotides, thus, it could be used to increase the sensitivity of cancer cells to this anti-pyrimidine agent. In this study, an expression vector containing the human TP cDNA was transfected into C26 murine colon-carcinoma cells. Stable transfectants were selected; all showed increased TP activity, ranging from 2- to 10-fold when compared with wild-type cells. The in vitro sensitivity of transfectants to 5-FU and 5'-deoxy-5-fluorouridine (5'-DFUR) was enhanced, in agreement with the observed increase in TP activity. Then, tumors were generated by s.c. injection of TP-transfected or wild-type C26 cells in syngeneic BALB/c mice. 5-FU (25 mg/kg, i.p.) induced a growth delay of TP-transfected C26 tumors as compared with C26 wild-type tumors. These data suggest that TP could be transfected in tumor cells to increase the sensitivity to 5-FU for subsequent cancer gene therapy.

An in vitro nucleoside analog screening method for cancer gene therapy

Suicide genes that sensitize cells to drugs that are normally nontoxic at therapeutic levels represent an important approach in human gene therapy research. We have developed an in vitro screening assay to assess the modulation of nucleoside analogs after transfection of a vector expressing the herpes simplex virus thymidine kinase gene (HSV-TK). The thymidine kinase gene enhances nucleoside phosphorylation to nucleotides that kill cells by blocking DNA elongation. Cells lines used are 3T3-NIH fibroblasts (parental cells) and 3T3-TKc3 (HSV-TK gene-transfected 3T3-NIH). Two types of analysis are performed: a cytotoxicity assay, the neutral red uptake assay to assess the IC50 on the two cell lines, and an HPLC analysis coupled to a radiochemical flow detector to evaluate metabolic profiles after incubation of cells with tritiated analogs. Results show that cells expressing the HSV-TK gene are more sensitive than the parent cells to the effect of acyclovir or ganciclovir, the reference purine analog drugs, and also to the effect of pyrimidine analogs, bromodeoxyuridine, bromovinyldeoxyuridine, and ethyldeoxyuridine. Promising nucleoside analogs for gene therapy that can be achieved by HSV-TK could be evaluated using this model.

[Genital hemorrhage in girls before puberty. Apropos of 33 cases]

Vaginal bleeding in young girls without other signs of precocious sexual development is rare. We report a series of 33 cases observed during a 21 year period in the departments of pediatrics of the University of Lyon. Among the various etiologies, vaginal foreign bodies (10 cases, 30%) and vaginitis (10 cases, 30%) were the most frequent. There were 3 cases of benign vulvar tumors (9%) and 3 cases of malignant vaginal tumors (9%). In 3 cases the vaginal bleeding remained apparently idiopathic leading to the diagnosis of premature menarche. A retrospective evaluation of each case showed that history, physical examination and colposcopy would have rapidly established the correct diagnosis in 80 to 85% of cases; it is therefore concluded that laboratory and complex gynecologic investigations should be considered only after negative findings from these simple clinical tools in the evaluation of vaginal bleeding in prepubertal girls.

[Auto-immunity and ovarian failure (author's transl)]

The authors report the case of a 17 year-old girl presenting with primary amenorrhea. Investigations showed that it was due to auto-immune hypogonadism. Such an etiology is rarely found in ovarian insufficiencies. In the reported case, there was no other associated auto-immune disorder. Two types of anti-ovarian antibodies are known: antibodies to steroid-producing cells and antibodies to germ-cells. The first ones are found in patients presenting with auto-immune Addison's disease, and are directed against antigens common to ovary and adrenal glands and their presence does not imply ovarian dysfunction. The second ones are more specific and found chiefly in patients with sterility and amenorrhea; they are divided into 2 subgroups: antibodies against the cytoplasm of the ovacyte antibodies and antibodies against zona pellucida. In patients with primary ovarian insufficiency, the presence of such antibodies should always be investigated.