Development and initial validation of a screening tool for visual ability/performance of people with polyhandicap

BACKGROUND

Visual impairments are common in people with polyhandicap although they are poorly assessed. However, evaluation of the visual abilities of these people is critical to determining treatment for impairments.

OBJECTIVES

To develop and validate an easy-to-use visual-behavioural scale for assessing the visual abilities of people with polyhandicap.

METHODS

The development of the Visual Assessment for People with Polyhandicap (VA-PLH) involved 2 steps: i) construction of the scale and ii) field validation. Participant selection criteria were aged > 3 years, age at onset of cerebral lesion < 3 years, a combination of motor impairment and profound intellectual impairment associated with restricted mobility (Gross Motor Function Classification System levels [GMFCS] III, IV or V), and everyday life dependence (Functional Independency Measure [FIM] <55). Vision assessment by both an orthoptist and an ophthalmologist was the reference against which were analysed the items of the scale completed by local health care workers. Acceptability, validity, and reliability were analysed.

RESULTS

Amongst the 232 participants included, 217 had a complete assessment, and 33% were < 18 years of age. Ocular abnormalities were reported in 83% of participants. Visual ability was altered or insufficient in 60% of participants. The final version of the VA-PLH included 3 items related to visual reaction (Area Under Curve Receiver Operating Characteristic = 0.83). Participants were considered at-risk if they had at ≥ 1 of 3 signs present (sensitivity 83% and specificity 73%). The scale's reliability was satisfactory CONCLUSION: The VA-PLH scale provides an easy-to-use, reliable and valid measure of visual status for people with polyhandicap and may be used both in clinical practice and clinical research. In addition, this study provides an overview of the diversity of visual impairments in a large population of people with polyhandicap, showing that most experience visual challenges.

Pharmacological targeting of netrin-1 inhibits EMT in cancer

Epithelial-to-mesenchymal transition (EMT) regulates tumour initiation, progression, metastasis and resistance to anti-cancer therapy1-7. Although great progress has been made in understanding the role of EMT and its regulatory mechanisms in cancer, no therapeutic strategy to pharmacologically target EMT has been identified. Here we found that netrin-1 is upregulated in a primary mouse model of skin squamous cell carcinoma (SCC) exhibiting spontaneous EMT. Pharmacological inhibition of netrin-1 by administration of NP137, a netrin-1-blocking monoclonal antibody currently used in clinical trials in human cancer (ClinicalTrials.gov identifier NCT02977195 ), decreased the proportion of EMT tumour cells in skin SCC, decreased the number of metastases and increased the sensitivity of tumour cells to chemotherapy. Single-cell RNA sequencing revealed the presence of different EMT states, including epithelial, early and late hybrid EMT, and full EMT states, in control SCC. By contrast, administration of NP137 prevented the progression of cancer cells towards a late EMT state and sustained tumour epithelial states. Short hairpin RNA knockdown of netrin-1 and its receptor UNC5B in EPCAM+ tumour cells inhibited EMT in vitro in the absence of stromal cells and regulated a common gene signature that promotes tumour epithelial state and restricts EMT. To assess the relevance of these findings to human cancers, we treated mice transplanted with the A549 human cancer cell line-which undergoes EMT following TGFβ1 administration8,9-with NP137. Netrin-1 inhibition decreased EMT in these transplanted A549 cells. Together, our results identify a pharmacological strategy for targeting EMT in cancer, opening up novel therapeutic interventions for anti-cancer therapy.

PRELIMINARY INVESTIGATIONS OF TRANSPORT IN HETEROGENEOUS RANDOM MEDIA

Random media emerge in several applications in reactor physics and safety analysis. Most often, models of stochastic media assume spatial homogeneity, whereas real-world complex materials, such as fuel chunks resulting from core degradation, typically display apparent heterogeneities. In a series of previous works, we have shown that stochastic tessellations can be successfully used in order to describe the material properties of several classes of random media. In this paper we extend these results to the case of heterogeneous random media by using Voronoi tessellations with space-dependent seed distributions, allowing for spatial gradients.

Fat1 deletion promotes hybrid EMT state, tumour stemness and metastasis

FAT1, which encodes a protocadherin, is one of the most frequently mutated genes in human cancers^1-5. However, the role and the molecular mechanisms by which FAT1 mutations control tumour initiation and progression are poorly understood. Here, using mouse models of skin squamous cell carcinoma and lung tumours, we found that deletion of Fat1 accelerates tumour initiation and malignant progression and promotes a hybrid epithelial-to-mesenchymal transition (EMT) phenotype. We also found this hybrid EMT state in FAT1-mutated human squamous cell carcinomas. Skin squamous cell carcinomas in which Fat1 was deleted presented increased tumour stemness and spontaneous metastasis. We performed transcriptional and chromatin profiling combined with proteomic analyses and mechanistic studies, which revealed that loss of function of FAT1 activates a CAMK2-CD44-SRC axis that promotes YAP1 nuclear translocation and ZEB1 expression that stimulates the mesenchymal state. This loss of function also inactivates EZH2, promoting SOX2 expression, which sustains the epithelial state. Our comprehensive analysis identified drug resistance and vulnerabilities in FAT1-deficient tumours, which have important implications for cancer therapy. Our studies reveal that, in mouse and human squamous cell carcinoma, loss of function of FAT1 promotes tumour initiation, progression, invasiveness, stemness and metastasis through the induction of a hybrid EMT state.

Context Dependency of Epithelial-to-Mesenchymal Transition for Metastasis

Epithelial-to-mesenchymal transition (EMT) has been proposed to be important for metastatic dissemination. However, recent studies have challenged the requirement of EMT for metastasis. Here, we assessed in different models of primary skin squamous cell carcinomas (SCCs) whether EMT is associated with metastasis. The incidence of metastasis was much higher in SCCs presenting EMT compared to SCCs without EMT, supporting the notion that a certain degree of EMT is required to initiate the metastatic cascade in primary skin SCCs. Most circulating tumor cells presented EMT, whereas most lung metastasis did not present EMT, showing that mesenchymal-to-epithelial transition is important for metastatic colonization. In contrast, immunodeficient mice transplanted with SCCs, whether displaying EMT or not, presented metastasis. Altogether, our data demonstrate that the association of EMT and metastasis is model dependent, and metastasis of primary skin SCCs is associated with EMT.

Identification of the tumour transition states occurring during EMT

In cancer, the epithelial-to-mesenchymal transition (EMT) is associated with tumour stemness, metastasis and resistance to therapy. It has recently been proposed that, rather than being a binary process, EMT occurs through distinct intermediate states. However, there is no direct in vivo evidence for this idea. Here we screen a large panel of cell surface markers in skin and mammary primary tumours, and identify the existence of multiple tumour subpopulations associated with different EMT stages: from epithelial to completely mesenchymal states, passing through intermediate hybrid states. Although all EMT subpopulations presented similar tumour-propagating cell capacity, they displayed differences in cellular plasticity, invasiveness and metastatic potential. Their transcriptional and epigenetic landscapes identify the underlying gene regulatory networks, transcription factors and signalling pathways that control these different EMT transition states. Finally, these tumour subpopulations are localized in different niches that differentially regulate EMT transition states.

CT and MRI imaging at the acute phase of inaugural non-traumatic hepatic haemorrhages

PURPOSE

Although rare, non-traumatic hepatic haemorrhage is a known complication of liver tumors. In cases where the haemorrhage is the first clinical event, diagnostic work-up is critical.

MATERIAL AND METHODS

This retrospective study was conducted between July 2001 and March 2011. Acute phase CT-scan and MRI imaging in patients diagnosed with non-traumatic liver hematomas were interpreted with particular attention to the radio-semiotic characteristics of hematomas and liver lesions. Those findings were then confronted to the patients' final diagnoses.

RESULTS

Twelve patients were included (mean age of 42 years). In seven of them a suspect liver lesion was discovered in the acute CT-Scan or MRI imaging. All lesions were strongly hyper vascular.The haemorrhage revealed hepatocarcinoma in four patients, liver adenoma in two and focal nodular hyperplasia in an other.

CONCLUSION

It is important in spontaneous liver haemorrhage to consider the high probability of hepatocarcinoma or potentially malignant lesions even when the patient has no known hepatic disorders, and especially in young patients. The results of this study show that imaging is a key issue at the acute phase of inaugural non-traumatic hepatic haemorrhages and requires a simple but complete triphasic injected protocol.

[Screening by general practitioners in smoking among young people aged 12 to 16 years]

OBJECTIVE

To know whether general practitioners in the Nord-Pas-de-Calais realize screened for tobacco use among youth aged 12 to 16years.

METHOD

This is a cross-sectional study of 300 general practitioners in the region Nord-Pas-de-Calais (150 in each department). These physicians were randomly selected according to the quota method (with XLSTAT(©) software). Upon agreement, we send them, by various means (e-mail, fax or mail their choice), the questionnaire.

RESULTS

One hundred and fifty-seven (68%) questionnaires were returned. Thirty-seven percent (58) of physicians routinely asked their young patients, during questioning, if they smoke, 58.5% (92) sometimes and 4.5% (7) do not ask. Information on smoking was issued by 86% of physicians surveyed.

CONCLUSION

General practitioners perform a screening for tobacco use among young patients aged 12 to 16years. They face certain obstacles which the presence of parents during the consultation.

Computed tomography of the parathyroids: the value of density measurements to distinguish between parathyroid adenomas of the lymph nodes and the thyroid parenchyma

PURPOSE

To compare the densities of parathyroid adenomas, lymph nodes and the thyroid parenchyma during multi-phase cervico-thoracic computed tomography to determine the differentiating threshold values.

MATERIALS AND METHODS

This study comprises 30 patients operated for a parathyroid adenoma after computed tomography without injection and then 45 and 70 seconds after the injection of an iodine based contrast product (350 mgI/mL, 150 mL, 3 mL/s). The density of the adenomas, lymph nodes and thyroid was measured during the three phases (D0, D45, D70). The relative enhancement (RE) at 45 seconds was calculated: RE=(D45-D0)/D0.

RESULTS

A significant difference was found in the spontaneous density of the parathyroid adenomas of the thyroid (P<0.01) with a threshold value of 75 HU. A significant difference is found in the enhancement after injection of the adenomas and lymph nodes (P<0.01). The adenomas present an enhancement peak at 45 seconds while the maximum enhancement of the lymph nodes is at 70 seconds. At 45 seconds, a threshold value of 114 HU and an RE 125% allows them to be distinguished (sensitivity and specificity 0.96).

CONCLUSION

Measurement of the densities can differentiate between the parathyroid adenomas, lymph nodes and thyroid.

Activities of antistaphylococcal antibiotics towards the extracellular and intraphagocytic forms of Staphylococcus aureus isolates from a patient with persistent bacteraemia and endocarditis

Decreased susceptibility of Staphylococcus aureus to antistaphylococcal agents may be associated with inability to eradicate intracellular forms, which could explain therapeutic failures. This hypothesis was tested using clinical isolates obtained from a patient with persistent staphylococcal bacteraemia under therapy. Four isogenic isolates (three from tissue, one from blood) with increased MICs for vancomycin (1-4 mg/L) and for daptomycin (1-4 mg/L) were collected after an initial 16-day treatment with vancomycin-rifampicin-gentamicin, followed by 13-20 days of treatment with daptomycin-rifampicin-gentamicin. Isolates were tested for MICs and for: (i) vancomycin (BODIPY-FL-vancomycin) and daptomycin binding; (ii) cell wall turnover (loss of N-acetyl-d-[1-(14)C]glucosamine in 30 min after 1 h of labelling); and (iii) Triton X-100-induced autolysis. Extracellular (broth) and intracellular (THP-1 macrophages) activities of rifampicin, linezolid and fusidic acid at C(max), and of vancomycin, daptomycin, quinupristin-dalfopristin and oritavancin over a wide range of extracellular concentrations (with pharmacological modelling to determine E(max)), were measured at 24 h. Increases in vancomycin MICs correlated with increased drug binding, and decreased cell wall turnover and detergent-induced autolysis. Increases in daptomycin MICs correlated with decreased daptomycin binding. Intracellular activity was weak (E(max) <1 log(10) CFU decrease) for vancomycin against all isolates, and for daptomycin against isolates with MICs >1 mg/L. Among all antibiotics tested, only quinupristin-dalfopristin and oritavancin provided close to bactericidal intracellular activities (1.6-2.5 log(10) CFU decreases at C(max)). Determination of the intracellular susceptibility of S. aureus, combined with improved methods of diagnosis, could be useful when dealing with persistent staphylococcal infections and could improve therapy.

Infiltration foraminale L5-S1 radioguidée dans le traitement de la lombosciatique S1

OBJECTIVE

To assess the efficacy of fluoroscopy guided L5-S1 transforaminal steroid injections for the treatment of S1 radiculopathy secondary to intervertebral disk disorder.

METHOD

41 patients were included: prospective study (20 patients) and retrospective study (21 patients). All patients suffered from S1 radiculopathy secondary to nerve root compression by intervertebral disk material, as demonstrated by lumbar spine CT. The patients underwent 2 fluoroscopy guided L5-S1 transforaminal injections of steroid (Hydrocotancyl 125 mg), at 8 days interval.

RESULTS

60% of patients showed significant improvement of their painful radiculopathy at day 8 (n:41), 60-67% at day 30 (n:41) and 67% at day 90 (n:18).

CONCLUSION

Fluoroscopy guided L5-S1 transforaminal injection showed good efficacy in the treatment of S1 radiculopathy.

Biochemical and histological responses in mussel (Mytilus edulis) exposed to North Sea oil and to a mixture of North Sea oil and alkylphenols

Several environmental chemicals are suspected to be responsible for adverse health effects on the reproductive system in various organisms. During this work, environmentally relevant concentrations of North Sea oil were used alone or in combination with alkylphenols and additional PAH to study the effect on vitellogenin-like protein expression and gonadal development in mussels. North Sea oil (0.5 ppm) induced the expression of phospho-proteins in both sexes indicating that some compounds are oestrogen-mimics. This induction was not seen in samples dosed with the mixture but signs of toxic effects were observed in the gonads. Indeed, numerous degenerating ovarian follicles in females and foci, similar to vertebrate melanomacrophage centres, were observed in testes.

Target-controlled infusion of propofol and remifentanil in cardiac anaesthesia: influence of age on predicted effect-site concentrations

BACKGROUND

Propofol-anaesthesia administrated via target-controlled infusion (TCI) has been proposed for cardiac surgery. Age-related changes in pharmacology explain why propofol dose requirement is reduced in elderly patients. However, the Marsh pharmacokinetic model incorporated in the Diprifusor propofol device does not take age into account as a covariable. In the absence of depth of anaesthesia monitoring, this limitation could cause adverse cardiovascular effects resulting from propofol overdose in older patients. We assessed the influence of age on effect-site propofol concentrations predicted by the Diprifusor and titrated to the bispectral index score (BIS) during cardiac anaesthesia.

METHODS

Forty-five patients received propofol by Diprifusor and remifentanil by software including Minto model. Propofol and remifentanil effect-site concentrations were adapted to BIS (40-60) and haemodynamic profile, respectively. The influence of age on effect-site concentrations was assessed by dividing patients into two groups: young (<65 yr) and elderly (> or =65 yr).

RESULTS

For a similar depth of anaesthesia, effect-site propofol concentrations were significantly lower in elderly patients at the different stages of cardiac surgery. The mean dose of propofol required to perform tracheal intubation was significantly lower in elderly patients. However, the overall doses of propofol were comparable in both groups. Neither effect-site remifentanil concentrations nor overall doses of remifentanil were significantly different between the two groups.

CONCLUSIONS

In cardiac anaesthesia, target concentrations of propofol must be reduced in elderly patients. Although this probably contributes to improving intraoperative haemodynamic stability, the absence of decrease in overall dose requirement of propofol suggests that this adjustment is relatively moderate.

Quality of life in multiple sclerosis: influence of interferon-beta1 a (Avonex) treatment

BACKGROUND

Numerous data argue for initiating treatment with interferon-beta (IFN-beta) at an early stage in multiple sderosis (MS). The consequences of its use may negatively influence the MS patient's quality of life (QoL).

OBJECTIVE

To evaluate the QoL of MS patients before and after a one-year period of treatment with IFN-beta1a (Avonex).

PATIENTS AND METHODS

QoL was assessed using the SF-36 in 121 relapsing-remitting MS patients. We compared QoL before and after treatment and with data from a normal population. We also studied the possible influence of disease progression on the SF-36 scores.

RESULTS

One hundred six patients completed the study (87%). Compared to a normal population, patients were, at baseline, worse off for all QoL scales, varying from a minimum decrease of 0.73 SD in mental health, to a maximum decrease of 1.55 SD in general health. After treatment, we found no significant changes in any of the QoL scores, except for physical function, where we noted a slight but significant decrease (p = 0.03). Furthermore, there was no significant change either in the physical component summary (PCS) or mental component summary (MCS). The 'reported health transition' item was significantly improved compared to baseline (p = 0.001). At indusion, significant correlations were found between EDSS scores and scores of physical function (p < 0.001), role - physical (p < 0.01), general health and social function (both p < 0.01), and with the PCS (p < 0.01). Patients with dinical relapses and/or disability progression had a more significant decease in physical function (p < 0.05) and also in social function (p < 0.05).

CONCLUSION

The QoL, assessed by the SF-36 scale, is correlated with disability in MS. IFN-beta1a treatment (Avonex) has no negative effect on MS patient's QoL.

Early evaluation of dressage ability in different breeds

Dressage is one of the Olympic equestrian sports practiced in several countries using different horse breeds. Specific characteristics of the walk, trot and canter are required for dressage. It has been assumed that some of these traits could be selected for genetically and contribute to dressage performance. The purpose of this study was to compare the walk, trot and conformation characteristics in young horses of different breeds used for dressage. A total of 142 horses age 3 years were classified into 3 groups of breeds (German, French and Spanish saddle horses) and tested using the same procedure. The skeletal conformation measurements were made by image analysis. Gait variables of the walk and trot were measured by the accelerometric gait analysis system Equimetrix. Discriminant analysis could explain the variability between the groups by taking into account the walk (P<0.0003), trot (P<0.0001) and conformation variables (P<0.0001). Many gait and conformation variables were significantly different between the breeds. In summary, the German horses had gait characteristics more adapted for dressage competition, and the results of this group could be used as a reference for early evaluation in dressage. Purebred Spanish horses could be considered as a reference for collected gaits used for farm work and old academic dressage. The gait and conformation tests could be applied in a breeding or crossing plan to detect more accurately young horses with good dressage ability.

The effect of reins on kinetic variables of locomotion

The equestrian literature and reports of experienced riders indicated that attitude of a horse's head and neck is related to the equine locomotion characteristics. The purpose of this study was to quantify the effects of 3 types of reins on locomotion at walk and trot. Eight saddle horses were tested in an automatic walker without reins, with rubber bands, Chambons and Back lift, using the same procedure. The rubber bands closed the head-neck angle, whereas the Chambons and the Back lift opened it. The gait characteristics were measured with the Equimetrix gait analysis system. Two accelerometric devices were fixed on the sternum and sacrum to measure the kinetic characteristics of the fore- and hindlimbs at walk and trot. Analysis of variance was used to test the effects of reins on the fore- and hindlimbs. All 3 types of reins significantly (P<0.05) modified walk and trot, with increased forelimb propulsion at the trot (P<0.05). Chambons increased the dorsoventral activity of the hindlimbs at the trot and hindlimb propulsion at the walk (P<0.05). Back lift increased forelimb dorsoventral activity both at the trot and walk (P<0.05). It was concluded that the Chambons increased the activity of the hindlimbs while Back lift increased that of the forelimbs. The use of reins modified the head placement and the fore- and hindlimbs activity. The specific effect of each type of rein can be used for training, rehabilitation or management of locomotor's injury.

Ceramide generation occurring during 7beta-hydroxycholesterol- and 7-ketocholesterol-induced apoptosis is caspase independent and is not required to trigger cell death

Biological activities of oxysterols seem tightly regulated. Therefore, the ability to induce cell death of structurally related oxysterols, such as those oxidized at C7(7alpha-, 7beta-hydroxycholesterol, and 7-ketocholesterol), was investigated on U937 cells at different times of treatment in a concentration range of 5-80 microg/ml. Whereas all oxysterols accumulate inside the cells, strong inhibition of cell growth and increased permeability to propidium iodide were observed only with 7beta-hydroxycholesterol and 7-ketocholesterol, which trigger an apoptotic process characterized by the occurrence of cells with fragmented and/or condensed nuclei, and by various cellular dysfunctions: loss of mitochondrial transmembrane potential, cytosolic release of cytochrome c, activation of caspase-9 and -3 with subsequent enhanced activity of caspase-3, degradation of poly(ADP-ribose) polymerase, and increased accumulation of cellular C16 : 0 and C24 : 1 ceramide species. This ceramide generation is not attributed to caspase activation since inhibition of 7beta-hydroxycholesterol- and 7-ketocholesterol-induced apoptosis by Z-VAD-fmk (100 microM), a broad spectrum caspase inhibitor, did not reduce C16 : 0 and C24 : 1 ceramide species accumulation. Conversely, when U937 cells were treated with 7beta-hydroxycholesterol and 7-ketocholesterol in the presence of fumonisin B1 (100 microM), a specific inhibitor of ceramide synthase, C16 : 0 and C24 : 1 ceramide species production was completely abrogated whereas apoptosis was not prevented. Noteworthy, 7alpha-hydroxycholesterol induced only a slight inhibition of cell growth. Collectively, these results are consistent with the notion that the alpha or beta hydroxyl radical position of oxysterols oxidized at C7 plays a key role in the induction of the apoptotic process. In addition, our findings demonstrate that 7beta-hydroxycholesterol- and 7-ketocholesterol-induced apoptosis involve the mitochondrial signal transduction pathway and they suggest that C16 : 0 and C24 : 1 ceramide species generated through ceramide synthase play a minor role in the commitment of 7beta-hydroxycholesterol- and 7-ketocholesterol-induced cell death.

Phorbol ester treatment of HL 60 leukemia cells results in increase of beta-(1 --> 4)-galactosyltransferase

We previously showed that HL 60 leukemia cells exhibit various changes in their cellular glycans after phorbol 12-myristate 13-acetate (PMA) treatment. These changes could originate largely from changes in one or several glycosyltransferases. In this report, we show using enzymatic measures, fluorescence microscopy, immunoblotting and Northern blot that beta-(1 --> 4)-galactosyltransferase I (GalT I) activity was higher (> x 2) in PMA-treated compared with untreated HL 60 cells. Immunoblotting showed an increased intensity of the GalT I band at 49 kDa and Northern blot a weak increase of the GalT I transcript band, after PMA treatment. Moreover, Northern blot performed after actinomycin-D treatment of the cells, which inhibits transcription, suggests that the observed increase of GalT I expression could originate, in part, from increase of the stability of GalT I transcripts.

Non-opioid antinociceptive effects of supraspinal histogranin and related peptides: possible involvement of central dopamine D(2) receptor

The antinociceptive effects of intracerebroventricular (ICV) administration of histogranin (HN) and related peptides were assessed in the mouse writhing and tail-flick assays. In the writhing test, the peptides displayed dose-dependent analgesic effects with an AD(50) of 23.9 nmol/mouse for HN and the following order for other peptides: HN-(7-15)<histone H4-(86-100) approximately HN approximately HN-(7-10)<[Ser(1)]HN<osteogenic growth peptide (OGP) approximately HN-(1-10). HN-(6-9) and HN-(8-10) did not show any significant analgesic activity at 50 nmol/mouse. The importance of the C- and N-terminal amino acids in the analgesic activity of the peptides was demonstrated by the prolonged effects of HN and [Ser(1)]HN ( approximately 30 min) compared with those of HN fragments (HN-(7-15), HN-(1-10) and HN-(7-10): 5-10 min). The analgesic activity of [Ser(1)]HN (50 nmol/mouse) was not affected by the coadministration of opioid (naloxone, 1 nmol/mouse), NMDA (CPP, 0.3 and MK-801, 0.3 nmol/mouse) and D(1) (SCH-23390, 0.5 nmol/mouse) receptor antagonists, but it was significantly antagonized by the coinjection of the D(2) receptor antagonist raclopride (0.5 nmol/mouse). In the mouse tail-flick assay, HN and related peptides (50 nmol/mouse) also showed significant analgesic activity (15-35% MPE). The analgesic effect of [Ser(1)]HN was dose-dependent and, at 75 nmol/mouse, lasted for up to 45 min, and was partially blocked by the coadministration of raclopride (1 nmol/mouse), but not naloxone (2 nmol/mouse). In the mouse rotarod assay, relative high doses (75-100 nmol/mouse) of HN and related peptides did not significantly affect motor coordination. These results indicate that supraspinal administration of HN and related peptides induce significant non-opioid analgesic effects devoid of motor activity by a mechanism that involves the participation of central dopamine D(2) receptors.

Interactions of dynorphin A-(1-13) and nociceptin with cardiac D2 binding sites: inhibition of ischemia-evoked release of noradrenaline from synaptosomal-mitochondrial fractions

The effect of dynorphin A (Dyn A)-related peptides and nociceptin on the binding of the D2 receptor antagonist, [(3)H]raclopride, was examined in membrane preparations of rat heart. Non-linear regression saturation binding analysis of [(3)H]raclopride binding revealed the presence of a single high-affinity binding site with a K(d)of 4.1 n M and a B(max)of 220 fmol/mg protein. The D2 stereospecificity of [(3)H]raclopride binding was demonstrated by competition experiments using two enantiomer pairs of antagonists. (+)-Butaclamol (IC(50): 8.0 n M) and (-)-sulpiride (IC(50): 112.3 n M) were 27 000 and 24 times more potent than (-)-butaclamol (IC(50): >100 microm) and (+)-sulpiride (IC(50): 2666 n M), respectively. Nociceptin and Dyn A-(1-13) were also potent inhibitors of the binding of [3H]raclopride with shallow inhibition curves that fitted best with two sites model. Their order of potency on the low affinity site [alpha -Neo-endorphin>nociceptin>Dyn A-(2-13)>Dyn A-(1-13)>Dyn B>Dyn A-(6-10)] correlated well with their ability to inhibit the binding of [3H]nociceptin (r=0.82). The indirect nature of the inhibitory effects of the peptides on the D2 receptor was demonstrated by their inability to inhibit [(3)H]raclopride binding to a membrane preparation (Sf9 cells transfected with the human D2(long)receptor) that does not contain the ORL(1)receptor and the lack of effect of raclopride (0.1 n M-10 microm) on both [(3)H]nociceptin and [(3)H]Dyn A-(1-13) binding. Isolated cardiac mitochondrial-synaptosomal fractions submitted to ischemic conditions (1 m M iodoacetate +2 m M NaCN, 5 min at 37 degrees C) released 10.9% of their content in preloaded [(3)H]noradrenaline ([(3)H]NA). Dyn A-(1-13) (10 microm), nociceptin (10 microm) and the selective D2 receptor agonist, quinpirole (10 microm) were potent blockers of the release of [(3)H]NA evoked by the ischemic conditions. The inhibitory effect of Dyn A-(1-13), nociceptin and quinpirole were antagonized by the selective D2 receptor antagonist, raclopride (10 microm); whereas naloxone, at a concentration (1 microm) known to affect the ORL(1)receptor, blocked the effects of the peptides but not those of quinpirole. The results demonstrate the presence of D2 receptors in rat heart and suggest that Dyn A-(1-13) and nociceptin modulate ischemia-induced NA release by a mechanism that involves the participation of both ORL(1)and D2 receptors.

Pharmacological manipulation of Ins(1,4,5)P3 signaling mimics preconditioning in rabbit heart

Recent evidence revealed biphasic alterations in myocardial concentrations of the second messenger inositol (1,4,5)-trisphosphate [Ins(1,4,5)P3] with ischemic preconditioning (PC), i.e., increase during brief PC ischemia and decrease early during sustained test occlusion. Our aim was to determine whether an agonist and an antagonist of Ins(1,4,5)P(3) signaling (D-myo-inositol-1,4,5-trisphosphate hexasodium salt [D-myo-Ins(1,4, 5)P3] and 2-aminoethoxydiphenyl borate (2-APB), respectively), given such that they mimic this biphasic profile, would mimic infarct size reduction with PC. To test this concept, isolated, buffer-perfused rabbit hearts received no intervention (control), ischemic PC, D-myo-Ins(1,4,5)P3, D-myo-Ins(1,4,5)P(3) + PC, 2-APB, or 2-APB + PC. All hearts then underwent 30-min coronary occlusion and 2 h reflow, and infarct size was delineated by tetrazolium staining. In addition, the effects of D-myo-Ins(1,4,5)P3 and 2-APB on Ins(1,4,5)P3 signaling were evaluated in isolated fura 2-loaded rat cardiomyocytes. Mean infarct size was reduced with PC and in all D-myo-Ins(1,4,5)P3- and 2-APB-treated groups versus control (59 and 42-55%, respectively, vs. 80% of myocardium at risk, P < 0.05). Thus pharmacological manipulation of Ins(1,4,5)P3 signaling mimics the cardioprotection achieved with ischemic PC in rabbit heart.

Hepatic acute phase induction of murine beta-galactoside alpha 2,6 sialyltransferase (ST6Gal I) is IL-6 dependent and mediated by elevation of exon H-containing class of transcripts

Hepatic expression of CMP-NeuAc:Gal beta 1,4GlcNAc alpha 2,6-sialyltransferase (ST6Gal I) is induced as part of the acute phase response in mammals by mechanisms that remain poorly understood. Previous work suggests that murine liver ST6Gal I mRNA contains an additional and novel region that is not found on ST6Gal I mRNA from human HepG2 hepatoma cells and from rat liver. This novel region, residing 5' of the common Exon I sequence, is encoded by a discrete upstream exon, Exon H. Here we provide evidence that the Exon H-containing transcript is the murine counterpart of the human and rat ST6Gal I mRNAs transcribed from the hepatic-specific promoter, P1. Exon H-containing ST6Gal I mRNA is expressed in all three mice strains examined: balb/c, C57B46, and 129Sv. Furthermore, murine RNA tissue survey indicates that presence of Exon H-containing transcripts is restricted to the liver. When mice are subjected to subcutaneous injection of turpentine to elicit the hepatic acute phase response, greater than 4-fold elevation in liver ST6Gal I mRNA was observed. Consistent with the view that Exon H-containing transcripts is regulated by the murine P1 promoter, 5'-RACE analysis indicates that the majority of these transcripts contains the Exon H sequence. This is consistent with the view that Exon H-containing transcripts are regulated by the murine P1 region. To assess the mechanism of ST6Gal I response in the hepatic acute phase reaction, mice harboring lesions in both alleles of the IL-6 gene were examined. IL-6(-/-) animals expressed normal levels of ST6Gal I mRNA in liver, with Exon H-containing transcripts remaining the predominant mRNA isoform. However, hepatic ST6Gal I is not elevated upon turpentine injection in the IL-6(-/-) animals. These results indicate that ST6Gal I induction in mouse liver during the acute phase reaction is mediated predominantly by the IL-6 pathway, and results in the induction of the Exon H-containing class of ST6Gal I mRNA that is specific to the liver.

The internal Cys-207 of sorghum leaf NADP-malate dehydrogenase can form mixed disulphides with thioredoxin

The role of the internal Cys-207 of sorghum NADP-malate dehydrogenase (NADP-MDH) in the activation of the enzyme has been investigated through the examination of the ability of this residue to form mixed disulphides with thioredoxin mutated at either of its two active-site cysteines. The h-type Chlamydomonas thioredoxin was used, because it has no additional cysteines in the primary sequence besides the active-site cysteines. Both thioredoxin mutants proved equally efficient in forming mixed disulphides with an NADP-MDH devoid of its N-terminal bridge either by truncation, or by mutation of its N-terminal cysteines. They were poorly efficient with the more compact WT oxidised NADP-MDH. Upon mutation of Cys-207, no mixed disulphide could be formed, showing that this cysteine is the only one, among the four internal cysteines, which can form mixed disulphides with thioredoxin. These experiments confirm that the opening of the N-terminal disulphide loosens the interaction between subunits, making Cys-207, located at the dimer contact area, more accessible.

Interaction of thioredoxins with target proteins: role of particular structural elements and electrostatic properties of thioredoxins in their interplay with 2-oxoacid dehydrogenase complexes

The thioredoxin action upon the 2-oxoacid dehydrogenase complexes is investigated by using different thioredoxins, both wild-type and mutated. The attacking cysteine residue of thioredoxin is established to be essential for the thioredoxin-dependent activation of the complexes. Mutation of the buried cysteine residue to serine is not crucial for the activation, but prevents inhibition of the complexes, exhibited by the Clamydomonas reinhardtii thioredoxin m disulfide. Site-directed mutagenesis of D26, W31, F/W12, and Y/A70 (the Escherichia coli thioredoxin numbering is employed for all the thioredoxins studied) indicates that both the active site and remote residues of thioredoxin are involved in its interplay with the 2-oxoacid dehydrogenase complexes. Sequences of 11 thioredoxin species tested biochemically are aligned. The thioredoxin residues at the contact between the alpha3/3(10) and alpha1 helices, the length of the alpha1 helix and the charges in the alpha2-beta3 and beta4-beta5 linkers are found to correlate with the protein influence on the 2-oxoacid dehydrogenase complexes (the secondary structural elements of thioredoxin are defined according to Eklund H et al., 1991, Proteins 11:13-28). The distribution of the charges on the surface of the thioredoxin molecules is analyzed. The analysis reveals the species specific polarization of the thioredoxin active site surroundings, which corresponds to the efficiency of the thioredoxin interplay with the 2-oxoacid dehydrogenase systems. The most effective mitochondrial thioredoxin is characterized by the strongest polarization of this area and the highest value of the electrostatic dipole vector of the molecule. Not only the magnitude, but also the orientation of the dipole vector show correlation with the thioredoxin action. The dipole direction is found to be significantly influenced by the charges of the residues 13/14, 51, and 83/85, which distinguish the activating and inhibiting thioredoxin disulfides.

Different patterns of IL-1beta secretion, adhesion molecule expression and apoptosis induction in human endothelial cells treated with 7alpha-, 7beta-hydroxycholesterol, or 7-ketocholesterol

Among oxysterols oxidized at C7 (7alpha-, 7beta-hydroxycholesterol, and 7-ketocholesterol), 7beta-hydroxycholesterol and 7-ketocholesterol involved in the cytotoxicity of oxidized low density lipoproteins (LDL) are potent inducers of apoptosis. Here, we asked whether all oxysterols oxidized at C7 were able to trigger apoptosis, to stimulate interleukin (IL)-Ibeta and/or tumor necrosis factor (TNF)-alpha secretion, and to enhance adhesion molecule expression (intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin) on human umbilical venous endothelial cells (HUVECs). Only 7beta-hydroxycholesterol and 7-ketocholesterol were potent inducers of apoptosis and of IL-1beta secretion. TNF-alpha secretion was never detected. Depending on the oxysterol considered, various levels of ICAM-1, VCAM-1 and E-selectin expression were observed. So, oxysterols oxidized at C7 differently injure and activate HUVECs, and the alpha- or beta-hydroxyl radical position plays a key role in apoptosis and IL-1beta secretion.

Heart rate as a determinant of L-type Ca2+ channel activity: mechanisms and implication in force-frequency relation

Early studies in enzymatically isolated animal cardiomyocytes indicated that voltage-gated "L-type" Ca2+ currents (ICaL) can be upregulated following an increase of the frequency of activation. Recently, we evidenced a similar regulation of ICaL in human cardiomyocytes from both left and right ventricles and atria over a physiopathological range of stimulations (between 0.5 and 5 Hz). This regulation, enhanced by the beta-adrenergic stimulation, may be involved in the frequency-dependent potentiation of cardiac contractile force in the human healthy myocardium. We show here that the frequency-dependent regulation of ICaL is controlled by the level of phosphorylation, as well as dephosphorylation, of the Ca2+ channels. It was enhanced following activation of the protein kinase A activated by intracellular cyclic AMP (cAMP). Therefore, we anticipate that all agents stimulating cAMP production will favor this process, which was demonstrated here by activating 5HT-4 receptors using serotonin. Alternatively, it was also enhanced by the phosphatase inhibitor okadaic acid which prevents Ca2+ channels dephosphorylation. Alteration or abnormal modulation by beta-adrenergic receptor stimulation of the frequency-dependent facilitation of ICaL may partly explain the altered force-frequency relation described in heart failure.

Characterization of the high affinity [3H]nociceptin binding site in membrane preparations of rat heart: correlations with the non-opioid dynorphin binding site

The binding parameters of [3H]nociceptin were examined in membrane preparations of rat heart and compared with those of [3H]dynorphin A-(1-13) ([3H]Dyn A-(1-13)). Scatchard analysis of [3H]nociceptin binding revealed the presence of two distinct sites: a high affinity (Kd: 583 nM) low capacity (Bmax: 132 pmol/mg protein) site and a low affinity (Kd: 10,316 nM) high capacity (1552 pmol/mg protein) site. Dyn A and related peptides were potent competitors of the binding to the high affinity site with the following rank order of potency: alpha-neo-endorphin > Dyn A-(2-13) = Dyn A-(3-13) > Dyn A-(5-13) > Dyn A-(1-13) > Dyn A > Dyn B > Dyn A-(6-10) >> Dyn A-(1-8). Nociceptin was 6.7 times less potent than Dyn A with a Ki of 4.8 microM as compared with 0.72 microM for Dyn A. The order of potency of the various peptides in inhibiting [3H]nociceptin binding correlated well (r = 0.93) with their ability to complete with the binding of [3H]Dyn A-(1-13) (Dumont and Lemaire, 1993). In addition, the high affinity [3H]nociceptin and non-opioid [3H]Dyn A-(1-13) sites were both sensitive to NaCl (120 mM) and the phospholipase C (PLC) inhibitors, U-73122 and neomycin (100 microM). The binding activities were less affected by the weak PLC inhibitor, U-73343, and no effect was observed with the non-hydrolysable GTP analogs. Gpp(NH)p and GTP-gamma-S. Nociceptin (1-50 microM) was also shown to inhibit the uptake of [3H]noradrenaline ([3H]NA) by cardiac synaptosomal preparations. In spontaneously hypertensive rats (SHR), the potency of nociceptin in inhibiting [3H]NA uptake was increased by 1.6-fold as compared with Wistar Kyoto (WKY) control rats and such effect was accompanied by comparable increased levels of cardiac ORL1 mRNA and [3H]nociceptin high affinity sites. These changes correlated well with the previously observed increased levels of non-opioid cardiac [3H]Dyn A-(1-13) sites in SHR (1.3 times as compared with WKY) and increased potency of Dyn A-(1-13) in inhibiting [3H]NA uptake by cardiac synaptosomes in SHR (2.2-fold as compared with WKY) (Dumont and Lemaire, 1995). The results demonstrate that in rat heart the characteristics of the high affinity, low capacity [3H]nociceptin binding site are similar to those of the non-opioid Dyn binding site. The stimulation of this site by nociceptin, Dyn A or related peptides is more likely to produce a modulation of PLC activity and [3H]NA uptake and may participate to the pathophysiology of hypertension.

Glutathione is implied in the control of 7-ketocholesterol-induced apoptosis, which is associated with radical oxygen species production

In a number of experimental systems, inhibition of apoptosis by antioxidants has led to the production of radical oxygen species (ROS) in certain apoptotic forms of cell death. Since antioxidant therapies can reduce vascular dysfunctions in hypercholesterolemic patients who frequently have increased plasma levels of oxysterols constituting potent inducers of apoptosis, we speculate that oxysterol-induced apoptosis could involve oxidative stress. Here, we tested the protective effects of the aminothiols glutathione (GSH) and N-acetylcysteine (NAC), which are two potent antioxidants, on apoptosis induced by 7-ketocholesterol in U937 cells, and we present evidence indicating that oxidative processes are involved in 7-ketocholesterol-induced cell death. Thus, GSH and NAC prevented phenomenona linked to apoptosis such as reduction of cell growth, increase cellular permeability to propidium iodide, and occurrence of nuclear condensation and/or fragmentation, and they delayed internucleosomal DNA fragmentation. In addition, cell treatment with GSH impaired cytochrome c release into the cytosol and degradation of caspase-8 occurring during cell death. During 7-ketocholesterol-induced apoptosis, we also observed a rapid decrease in cellular GSH content, oxidation of polyunsaturated fatty acids, and a production of ROS by flow cytometry with the use of the dye 2', 7'-dichlorofluorescin-diacetate; both phenomena were inhibited by GSH. Prevention of cell death by GSH and NAC does not seem to be a general rule since these antioxidants impaired etoposide (but not cycloheximide) -induced apoptosis. Taken together, our data demonstrate that GSH is implied in the control of 7-ketocholesterol-induced apoptosis associated with the production of ROS.

The single mutation Trp35-->Ala in the 35-40 redox site of Chlamydomonas reinhardtii thioredoxin h affects its biochemical activity and the pH dependence of C36-C39 1H-13C NMR

The role of the invariant Trp residue at the redox site of thioredoxins was investigated by site-directed mutagenesis of a Chlamydomonas reinhardtii thioredoxin h. Though being still redox active with NADPH-thioredoxin reductase and chemical substrates [dithiothreitol and 5,5'-dithio-bis(2-nitrobenzoic acid)] the Trp35-->Ala-mutated protein completely lost the capacity to activate the thiol-regulated NADPH-dependent malate dehydrogenase. However, it was able to activate a mutant malate dehydrogenase where only the most exposed disulfide was retained. The pH dependence of the redox-site Cys beta 1H/13C-NMR frequencies of the wild-type and mutated proteins, in both the reduced and oxidised states, were compared over the pH range 5.8-10. The mutation does not affect the conserved buried Asp30, which titrates with a pKa of 7.5 in the oxidised proteins in agreement with previous studies. However, for the reduced forms of the proteins, the pH dependence of resonances of both Cys was strongly affected by the mutation. In the case of the wild-type thioredoxin, two apparent pKa values were found around 7.0 and 9.5 and could be assigned to the titration of Cys36 and Cys39 thiol, respectively, similar to the case of Escherichia coli thioredoxin. For the mutated thioredoxin a single pKa was found around 8.3. This result can be interpreted as a single pKa of either Cys36 or Cys39 or both. While the mutation clearly affects ionisations, the measured redox potentials of the active-site Cys pair are not significantly affected by the Trp35-->Ala mutation. Possible roles of an aromatic side chain on the reactivity of the catalytic Cys residues in thioredoxins are proposed.

Poly A-containing histone H4 mRNA variant (H4-v. 1): isolation and sequence determination from bovine adrenal medulla

A histone H4 cDNA variant (H4-v.1) was cloned from a bovine adrenal medullary phage library using PCR as a method of detection. The isolated clones contained a short 5' untranslated region (UTR) followed by the histone H4 coding region and a long atypical 3'UTR. The 3'UTR comprised the palindromic and purine-rich sequences typical of cell-cycle dependent histone mRNAs, and a 1.1 kb extension downstream of the palindromic sequence ending with a poly(A) track typical of cell-cycle independent histone mRNAs. Northern blot and RT-PCR analyses indicate that the transcript is fully expressed in bovine adrenal medulla. Thus, bovine histone H4-v.1 mRNA represents the first example of a histone H4 transcript that contains both 3'UTR characteristics of cell-cycle dependent and cell-cycle independent histone mRNAs.

T lymphocyte activation results in an increased expression of beta-1,4-galactosyltransferase: phorbol ester induces a similar enhancement in the absence of mitosis

We previously showed that in vitro activated human T lymphocytes expressed increased amounts of beta-1,6-branched N-linked oligosaccharides (Lemaire S etal. (1994) J Biol Chem269: 8069-74), which have been proposed to participate in the regulation of the immune process. In the present paper, we compared the activity and expression of beta-1,4-galactosyltransferase (GalT), one of the glycosyltransferases involved in the biosynthesis of these beta-1,6-branched N-linked oligosaccharides, before and after in vitro activation of T lymphocytes after a 40h treatment with a mixture of phorbol 12-myristate 13-acetate and Phaseolus vulgaris lectin. After treatment, the enzymatic activity of the GalT was significantly increased and immunoblot experiments performed with a monoclonal antibody to human GalT showed an increased intensity of the GalT band at 49 kDa, attributable to an enhancement of GalT mRNA level, as shown by Northern blots. However, treatment of the same T-lymphocytes by phorbol ester alone, which is unable to induce mitosis, resulted in a comparable increase of the expression of GalT. Moreover, these phorbol ester-treated T lymphocytes, analysed by flow cytometry exhibited a two-fold increase in the expression of GalT. Finally, confocal fluorescence microscopy performed on all T lymphocytes (treated or not) showed that the flow cytometric signal of GalT originates from intracellular, Golgi-associated antigen only since no surface GalT was detected.