Basal forebrain cholinergic neurons have specific characteristics during the perinatal period

Cholinergic neurons of the basal forebrain (BF) represent the main source of cholinergic innervation of large parts of the neocortex and are involved in adults in the modulation of attention, memory, and arousal. During the first postnatal days, they play a crucial role in the development of cortical neurons and cortical cytoarchitecture. However, their characteristics, during this period have not been studied. To understand how they can fulfill this role, we investigated the morphological and electrophysiological maturation of cholinergic neurons of the substantia innominata-nucleus basalis of Meynert complex (SI/NBM) in the perinatal period in mice. We show that cholinergic neurons, whether or not they express γ-aminobutyric acid (GABA) as a co-transmitter, are already functional at embryonic day 18 (E18). Until the end of the first postnatal week, they constitute a single population of neurons with a well-developed dendritic tree, a spontaneous activity including bursting periods, and a short latency response to depolarizations (early-firing). They are excited by both their GABAergic and glutamatergic afferents. During the second postnatal week, a second, less excitable, neuronal population emerges, with a longer delay response to depolarizations (late-firing), together with the hyperpolarizing action of GABAAR-mediated currents. This classification into early-firing (40%) and late-firing (60%) neurons, is again independent of the co-expression of GABAergic markers. These results strongly suggest that during the first postnatal week, the specific properties of developing SI/NBM cholinergic neurons allow them to spontaneously release acetylcholine, or acetylcholine and GABA, into the developing cortex.Significance statement During early postnatal days, basal forebrain cholinergic neurons from the substantia innominata-nucleus basalis of Meynert complex (SI/NBM) play a crucial role in cortical development. However, their morphological and electrophysiological characteristics have not been studied during this period. Here we show that perinatal SI/NBM cholinergic, whether they still/have co-expressed GABAergic markers, belong to a single, homogeneous population of spontaneously active, early-firing, bursting neurons, activated by both glutamatergic and GABAergic afferents until the GABAARs-mediated current polarity shift from excitatory to inhibitory has occurred. This early high excitability suggests that they can release acetylcholine or acetylcholine and GABA into the developing cortical layers and fulfill their well-described role on the early development of cortical neurons and networks.

23 THE EFFECT OF WITHDRAWAL TIMING OF CONTROLLED INTERNAL DRUG RELEASE (CIDR) ON EWE REPRODUCTIVE PERFORMANCE

This study was carried out using 80 multiparous Awassi ewes during breeding season to compare the effects of controlled internal drug release (CIDR) withdrawal time on ewe fertility. Ewes were equally and randomly allotted into 4 groups (n = 20/group). Ewes had a CIDR inserted for 3, 6, 9, or 12 days with intramuscular administration of 300 IU of equine chorionic gonadotropin (eCG) at withdrawal time. Oestrus was detected using vasectomized ram starting 12 h after CIDR withdrawal and repeated every 12 h up to 84 h. Blood samples were collected from all groups at the time of CIDR withdrawal for measuring of oestradiol (E2) and progesterone (P4) serum concentrations using commercial ELISA kits and micro-titrimetric plates. Timed insemination was performed 48 h post CIDR withdrawal in all groups. Pregnancy was diagnosed by ultrasonography at day 23 post-insemination and confirmed at day 35. Comparisons among groups were evaluated using Chi Square (χ2) test in all measured parameters except hormones levels, which analysed by repeated-measures analysis of variance (ANOVA), using SAS (SAS Institute Inc., Cary, NC, USA). A difference was considered significant at P < 0.05 level. The results revealed that the retention, vaginal discharge and drawstring breakage rates after CIDR removal were insignificantly differed between all groups. On the other hand, pregnancy rate was significantly (P ≤ 0.05) higher in 9-d and 6-d groups (68.4 and 60%, respectively) than the 3-d group. While, no significant difference was detected between 12d group and other groups. The heat detection rate was significantly (P ≤ 0.05) higher in 12d group (100%) than 6-d and 3-d groups (80 and 45%, respectively). While, no significant difference was detected between 12-d and 9-d groups in heat detection rate. P4 was significantly higher in the 12-d group (13.4 ± 3.06 ng mL−1) than other groups. While E2 was significantly lower in the 12-d group (1.6 ± 0.06 pg mL−1) than other groups. These results indicated that withdrawal of CIDR devices after 9 days are efficient in synchronizing oestrus in ewes and provided higher pregnancy rate.

Quantitative real-time polymerase chain reaction as an efficient molecular tool for detecting minimal residual disease in Moroccan chronic myeloid leukemia patients

Chronic myeloid leukemia (CML) is characterized by BCR-ABL translocation and an increased number and migration of immature myeloid cells into the peripheral blood. The detection limit of the BCR-ABL transcript, particularly after treatment, is controversial. In the present study, we used quantitative real-time reverse transcription-polymerase chain reaction (RT-qPCR) to monitor BCR-ABL expression in Moroccan CML patients undergoing imatinib treatment, and compared the results with those of conventional PCR and fluorescence in situ hybridization (FISH). The aim of this study was to establish a new molecular tool for in vitro diagnosis of CML. In a retrospective comparative analysis, 20 CML Moroccan patients who had received imatinib treatment (N = 20) were analyzed by real-time PCR, conventional RT-PCR, and FISH. Half of the samples analyzed (N = 10) were positive for BCR-ABL gene expression, while the other half (N = 10) were negative according to conventional PCR. Interestingly, 5 of the 10 samples shown to be negative by conventional PCR showed positive expression of the BCR-ABL gene according to RT-qPCR. The RT-qPCR results were confirmed by FISH, which revealed a high concordance (100%) rate. We found that real-time RT-qPCR is more reliable and should be used in Moroccan biomedical analysis laboratories to monitor CML progression, particularly for minimal residual disease, following imatinib treatment.

[Paraneoplastic Cushing's syndrome, a real diagnostic and therapeutic challenge: A case report and literature review]

INTRODUCTION

Paraneoplastic Cushing's syndrome is a rare cause of endogenous hypercortisolism attributable to ectopic ACTH secretion by non-pituitary tumors. Imaging and biochemical results are often inconclusive and differential diagnosis with Cushing's disease can then be challenging. Moreover, these tumors may be occult and difficult to find and thus the need of new imaging tools such as (18)FDG-PET scan and (18)DOPA-PET scan.

CASE REPORT

We report a 50-year-old man who presented with very aggressive clinical features related to Cushing's syndrome. Biological work-up confirmed the hypercortisolism and was consistent with an ectopic ACTH secretion. Conventional localization techniques failed to show any tumor and bilateral adrenalectomy was performed because of life-threatening complications. Two years later, thoracic computed tomography reveals an 11 mm mass in the left lower pulmonary lobe, (18)FDG-PET scan found a non-specific mild hypermetabolism of the lung nodule, and the (18)DOPA-PET scan confirmed the high uptake of this nodule suggesting an endocrine carcinoma. Histology confirmed a typical carcinoid tumor. The tumor cells stained positive for ACTH, CD56, chromogranin and synaptophysin.

CONCLUSION

This case illustrates the dilemma between the need for morphological diagnosis of the ectopic ACTH source and control of the life-threatening hypercortisolism. (18)FDG-PET scan and (18)DOPA-PET scan should be considered early as a secondary diagnostic tool when conventional imagery fails to show any tumor.

Somatic and axonal LIGHT signaling elicit degenerative and regenerative responses in motoneurons, respectively

A receptor-ligand interaction can evoke a broad range of biological activities in different cell types depending on receptor identity and cell type-specific post-receptor signaling intermediates. Here, we show that the TNF family member LIGHT, known to act as a death-triggering factor in motoneurons through LT-βR, can also promote axon outgrowth and branching in motoneurons through the same receptor. LIGHT-induced axonal elongation and branching require ERK and caspase-9 pathways. This distinct response involves a compartment-specific activation of LIGHT signals, with somatic activation-inducing death, while axonal stimulation promotes axon elongation and branching in motoneurons. Following peripheral nerve damage, LIGHT increases at the lesion site through expression by invading B lymphocytes, and genetic deletion of Light significantly delays functional recovery. We propose that a central and peripheral activation of the LIGHT pathway elicits different functional responses in motoneurons.

Specific BRCA1 gene variations amongst young Moroccan breast cancer patients

Germline mutations in the BRCA1 gene are known predictive markers for the development of hereditary breast cancer. Nevertheless, no comprehensive study has been performed targeting the presence and relevance of BRCA1 mutations in Moroccan breast cancer patients. We here present an analysis of BRCA1 gene regions (exon 2 and exon 11a/b) of 50 female Moroccan breast cancer patients with early disease onset (≤ 40 years) or familial disease backgrounds. Results showed that no mutation was present in either exon 2 or exon 11a of the BRCA1 gene in any of the 50 patients analysed. However, in exon 11b, a mutation generated by a nucleotide exchange was detected in 8% of patients, most of whom were young women (≤ 40). This mutation leads to substitution of the amino acid glutamine by an arginine at position 356 of the polypeptide sequence (Q356R). Although this mutation was previously characterised at a lower frequency in western populations, our study is the first to describe it in a young Moroccan population. Furthermore, another mutation was detected with a high frequency (4%) on exon 11b of the BRCA1 gene in exclusively young patients (≤ 40). This mutation was silent, encoding the same threonine residue at position 327 (T327T) as the wild type. The present study is the first to describe this mutation as well, particularly in a young Moroccan population. Analysis of a larger population is required in order to highlight the relevance of the Q356R and T327T mutations in young Moroccan breast cancer patients.

Role of both actin-myosin cross bridges and NO-cGMP pathway modulators in the contraction and relaxation of human placental stem villi

INTRODUCTION

Human placental stem villi (PSV) present contractile properties. We studied the role of actin-myosin cross bridges (CBs) and the effects of NO-cGMP pathway modulators in the PSV contraction and relaxation.

METHODS

In vitro contractile properties were investigated in 71 PSV from term human placentas studied according to their long axis. Contraction was induced by both KCl and electrical tetanic stimulation. Relaxation was induced by inhibiting the CB cycle with either 2,3-butanedione monoxime (BDM) or blebbistatin (BLE) and by activating the NO-cGMP pathway with isosorbide dinitrate (ISDN), sildenafil (SIL) or ISDN + SIL.

RESULTS

PSV tension slowly increased by 140% of the basal tone after KCl exposure and by 85% after tetanus. The addition of BDM, BLE, ISDN, SIL and ISDN + SIL induced a relaxation of PSV, the overall time course of relaxation (in s) was respectively (means ± SD) 3412 ± 1904, 14,250 ± 3095*, 3813 ± 1383, 2883 ± 1188 and 2440 ± 477; significantly longer in BLE compared with BDM, ISDN, SIL and ISDN + SIL:*p < 0.001). the overall time course of relaxation (in s) was respectively (means ± SD) 3412 ± 1904, 14,250 ± 3095*, 3813 ± 1383, 2883 ± 1188 and 2440 ± 477; significantly longer in BLE compared with BDM, ISDN, SIL and ISDN + SIL:*p < 0.001). These relaxation kinetics were particularly slow. Other relaxation parametres, i.e., maximum lengthening, -peak dT/dt, and resting tension, did not differ between these 5 subgroups.

DISCUSSION AND CONCLUSION

Isolated human PSV were able to contract after both KCl exposure and tetanus. This increase in contractility was reversed by inhibiting the CB cycle with BDM or BLE and by stimulating the NO-cGMP pathway with ISDN or SIL. The association ISDN + SIL did not potentiate the relaxing processes.

Met acts through Abl to regulate p53 transcriptional outcomes and cell survival in the developing liver

BACKGROUND & AIMS

Genetic studies indicate that distinct signaling modulators are each necessary but not individually sufficient for embryonic hepatocyte survival in vivo. Nevertheless, how signaling players are interconnected into functional circuits and how they coordinate the balance of cell survival and death in developing livers are still major unresolved issues. In the present study, we examined the modulation of the p53 pathway by HGF/Met in embryonic livers.

METHODS

We combined pharmacological and genetic approaches to biochemically and functionally evaluate p53 pathway modulation in primary embryonic hepatocytes and in developing livers. RT-PCR arrays were applied to investigate the selectivity of p53 transcriptional response triggered by Met.

RESULTS

Met recruits p53 to regulate the liver developmental program, by qualitatively modulating its transcriptional properties: turning on the Mdm2 survival gene, while keeping death and cell-cycle arrest genes Pmaip1 and p21 silent. We investigated the mechanism leading to p53 regulation by Met and found that Abl and p38MAPK are required for p53 phosphorylation on S(389), Mdm2 upregulation, and hepatocyte survival. Alteration of this signaling mechanism switches p53 properties, leading to p53-dependent cell death in embryonic livers. RT-PCR array studies affirmed the ability of the Met-Abl-p53 axis to modulate the expression of distinct genes that can be regulated by p53.

CONCLUSIONS

A signaling circuit involving Abl and p38MAPK is required downstream of Met for the survival of embryonic hepatocytes, via qualitative regulation of the p53 transcriptional response, by switching its proapoptotic into survival properties.

Elevated levels of IFNγ and LIGHT in the spinal cord of patients with sporadic amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a paralytic and fatal neurodegenerative disorder caused by the gradual loss of both upper and lower motoneurons. There is compelling evidence from ALS experimental models that neuroinflammation actively contributes to motoneuron damage. We recently proposed that interferon gamma (IFNγ), a potent proinflammatory cytokine, induces motoneuron death by eliciting the activation of the lymphotoxin beta receptor (LT-βR) through its ligand LIGHT. Here, we explore the pertinence of this non-cell-autonomous mechanism in human ALS.

METHODS

The levels and expression pattern of IFNγ, LIGHT, and LT-βR were investigated by Western blot and immunohistochemical analysis in spinal cord of patients with sporadic ALS.

RESULTS

  We observed significant increased levels of IFNγ in human ALS spinal cords compared to control cases. We found that large ventral horn neurons as well as glial cells were immunoreactive for IFNγ in sporadic ALS spinal cord. We further observed that LIGHT and LT-βR were expressed mainly by motoneurons in both ALS and control cases, and while LT-βR levels remained constant between ALS and control cases, LIGHT levels were increased in human ALS spinal cords.

CONCLUSION

These findings in sporadic ALS cases, which are consistent with the observation made in ALS experimental models, propose that the IFNγ-triggered LIGHT/LT-βR-mediated death pathway may contribute to human ALS pathogenesis.

AAV-mediated expression of wild-type and ALS-linked mutant VAPB selectively triggers death of motoneurons through a Ca2+-dependent ER-associated pathway

A dominant mutation in the gene coding for the vesicle-associated membrane protein-associated protein B (VAPB) was associated with amyotrophic lateral sclerosis, a fatal paralytic disorder characterized by the selective loss of motoneurons in the brain and spinal cord. Adeno-associated viral vectors that we show to transduce up to 90% of motoneurons in vitro were used to model VAPB-associated neurodegenerative process. We observed that Adeno-associated viral-mediated over-expression of both wild-type and mutated form of human VAPB selectively induces death of primary motoneurons, albeit with different kinetics. We provide evidence that ER stress and impaired homeostatic regulation of calcium (Ca(2+)) are implicated in the death process. Finally, we found that completion of the motoneuron death program triggered by the over-expression of wild-type and mutant VAPB implicates calpains, caspase 12 and 3. Our viral-based in vitro model, which recapitulates the selective vulnerability of motoneurons to the presence of mutant VAPB and also to VAPB gene dosage effect, identifies aberrant Ca(2+) signals and ER-derived death pathways as important events in the motoneuron degenerative process.

Comparison of bacterial pellets and microbial markers for the estimation of the microbial nitrogen and amino acids flows from single flow continuous culture fermenters fed diets containing two-stage olive cake

The effects of using effluent bacteria (EB) and solid- (SAB) and liquid- (LAB) associated bacteria and diaminopimelic acid (DAPA) or purine bases (PB) and partially substituting alfalfa hay (AH) by a concentrate including olive cake on the microbial N flow (MNF) and amino acids (AA) flow were investigated with continuous culture fermenters fed AH and a mixture of AH and a concentrate containing barley grains and two-stage olive cake (2:1 ratio) without (AHCO) or with polyethylene glycol (PEG) (AHCOP). The MNF was not different among diets with SAB or LAB (p = 0.302 and 0.203, respectively) and DAPA, but differed with PB (p = 0.021 and 0.014, respectively). With EB both markers detected similar differences, AHCOP showing a higher value (p < 0.05) than AH and AHCO. The MNF was higher (p < 0.001) with PB than DAPA. Daily flow of non-essential AA was not different (p = 0.356) among diets but essential AA flow was higher (p < 0.05) for AH and AHCOP than for AHCO. The SAB presented lower (p < 0.05) total AA than LAB and higher total AA (p < 0.05) for diet AH than AHCO. The AA profile of EB was similar to that of LAB, but alanine and leucine were higher (p < 0.05) in EB than in LAB. Microbial contribution to AA flow was 45.4%, 55.6% and 58.1% for diets AH, AHCO and AHCOP respectively. With both markers, microbial AA flow was higher (p < 0.05) for diet AHCOP compared with AH (451 and 355 mg/day, respectively), but not different (p > 0.05) for AHCOP and AHCO (389 mg/day). The results would indicate that olive cake could be used in the practical feeding of small ruminants without negatively affecting microbial AA N supply.

Fermentation characteristics and microbial growth promoted by diets including two-phase olive cake in continuous fermenters

Two-phase olive cake (2POC) is the by-product obtained from the so called 'two-phase' procedure to extract olive oil by mechanical methods. After the mechanical extraction the 2POC is dried and most of the remaining oil extracted by chemical means. The production of the crude by-product may reach more than 4 millions t/year in Spain (MAPA, 2003), most of it in areas (Southeast) with shortage of pastures and conventional feeds for ruminants. Six continuous fermenters, inoculated with ruminal liquor from wethers or goats, were fed lucerne hay (LH); LH plus a concentrate including dried two-phase olive cake (LHCO) and; diet LHCO added with polyethylene glycol (LHCOP). The highest pH values and ammonia N (NH(3)-N) output were found in fermenters fed diet LH (6.19 and 6.35 for pH, and 53.7 and 68.9 mg NH(3)N/day, respectively, in fermentes inoculated with rumen liquor from sheep and goats) without differences due to the inoculum origin. The digestibility of carbohydrates (CHO) was affected (p < 0.001) by inoculum (67.0 and 58.8%, respectively, for goats and wethers) the lowest values being for diet LHCO (53.2 and 57.0% with inoculum from wethers and goats, respectively). The main volatile fatty acid (VFA) was acetic acid with higher (p < 0.01) values in fermenters with inoculum from goats than from wethers (80.2 and 63.0 mmol/day respectively). The efficiency of bacterial protein synthesis (EBS) was not different (p > 0.05) with inoculum from wethers and goats [26.4 and 28.1 and 35.2 and 33.5 g bacterial N/kg digested CHO, respectively, obtained by using diamino pimelic acid (DAPA) and purine bases (PB) as microbial markers]. The lowest (p < 0.05) values were found in fermenters fed diets LHCOP and LH, estimated, respectively, from DAPA and PB (21.9 and 29.0 g bacterial N/kg digested CHO). The substitution of a part of lucerne hay by a concentrate including dried 2POC does not seem to cause important differences in efficiency of VFA production. Results concerning bacterial protein synthesis are not so clear since values estimated from DAPA and PB did not show similar trends. Neither inoculum origin nor PEG had important effects on fermentation characteristics. The DAPA could be an adequate marker in continuous fermenters, with comparative purposes, as protozoa are not present and, estimated protein synthesis values are similar to those obtained in vivo with similar diets using urinary excretion of PD (Yáñez Ruiz et al., 2004b). Further research is needed to state the optimal proportion of 2POC in practical diets for ruminants at both maintenance and production stages.

Met signals hepatocyte survival by preventing Fas-triggered FLIP degradation in a PI3k-Akt-dependent manner

The FasL-Fas couple is a general death mediator whose activated signals lead to caspase-8 activation and apoptosis in adult hepatocytes. Suppression of caspase-8 activation and cell death is a protective mechanism modulated by the FLICE-Like Inhibitory Protein (FLIP). Although hepatocyte growth factor (HGF) and its receptor Met are known to mediate cell survival in developing livers, the molecular mechanisms involved in this process are poorly understood. We show here that Met activation by HGF impairs Fas-triggered apoptosis of primary embryonic hepatocytes and cell survival correlates with inhibition of caspase-8 and caspase-3 activities. Furthermore, we found that HGF treatment prevents degradation of FLIPL triggered by Fas activation. In contrast to this, Met activation does not modulate FLIPL levels and its stability in untreated cells, thus showing the specificity of this regulatory mechanism for embryonic hepatocyte survival. Knocking down FLIP expression abolishes the ability of Met to inhibit Fas-triggered hepatocyte death, demonstrating the functional requirement of FLIP in HGF anti-apoptotic signals. By combining genetic and pharmacological approaches, we also demonstrate that the PI3K-Akt pathway is required in embryonic hepatocytes to prevent Fas-triggered FLIP degradation and death. Thus, Met acting on PI3K and Akt ensures high levels of FLIPL, and disruption of this pathway contributes to hepatic apoptosis and possibly to Fas-related liver diseases.

Met acts on Mdm2 via mTOR to signal cell survival during development

Coordination of cell death and survival is crucial during embryogenesis and adulthood, and alteration of this balance can result in degeneration or cancer. Growth factor receptors such as Met can activate phosphatidyl-inositol-3' kinase (PI3K), a major intracellular mediator of growth and survival. PI3K can then antagonize p53-triggered cell death, but the underlying mechanisms are not fully understood. We used genetic and pharmacological approaches to uncover Met-triggered signaling pathways that regulate hepatocyte survival during embryogenesis. Here, we show that PI3K acts via mTOR (Frap1) to regulate p53 activity both in vitro and in vivo. mTOR inhibits p53 by promoting the translation of Mdm2, a negative regulator of p53. We also demonstrate that the PI3K effector Akt is required for Met-triggered Mdm2 upregulation, in addition to being necessary for the nuclear translocation of Mdm2. Inhibition of either mTOR or Mdm2 is sufficient to block cell survival induced by Hgf-Met in vitro. Moreover, in vivo inhibition of mTOR downregulates Mdm2 protein levels and induces p53-dependent apoptosis. Our studies identify a novel mechanism for Met-triggered cell survival during embryogenesis, involving translational regulation of Mdm2 by mTOR. Moreover, they reinforce mTOR as a potential drug target in cancer.

Imino-tetrahydro-benzothiazole derivatives as p53 inhibitors: discovery of a highly potent in vivo inhibitor and its action mechanism

Several neurological disorders manifest symptoms that result from the degeneration and death of specific neurons. p53 is an important modulator of cell death, and its inhibition could be a therapeutic approach to several neuropathologies. Here, we report the design, synthesis, and biological evaluation of novel p53 inhibitors based on the imino-tetrahydrobenzothiazole scaffold. By performing studies on their mechanism of action, we find that cyclic analogue 4b and its open precursor 2b are more potent than pifithrin-alpha (PFT-alpha), which is known to block p53 pro-apoptotic activity in vitro and in vivo without acting on other pro-apoptotic pathways. Using spectroscopic methods, we also demonstrate that open form 2b is more stable than 4b in biological media. Compound 2b is converted into its corresponding active cyclic form through an intramolecular dehydration process and was found two log values more active in vivo than PFT-alpha. Thus, 2b can be considered as a new prodrug prototype that prevents in vivo p53-triggered cell death in several neuropathologies and possibly reduces cancer therapy side effects.

Novel cyclized Pifithrin-alpha p53 inactivators: synthesis and biological studies

Starting from various cyclic or bicyclic ketones, we have synthesized novel Pifithrin-alpha analogues bearing different methyl substituted phenyl ketone groups at the N3-position of the 2-iminothiazole heterocycle. From stability studies in a biological medium as well as under specific chemical conditions, we have shown by NMR techniques that through a dehydration process, some derivatives can generate their corresponding cyclized analogues. All of the new analogues, Pifithrin-like and polycyclic dehydrated derivatives were assessed for their p53 inactivation potency by measuring survival of cortical neurons, whose death was induced by the DNA-damaging agent etoposide. Pifithrin-alpha like 2f as well as the cyclic dehydrated 6b analogue were found to be one log more potent p53 inactivators than reference compound Pft-alpha, with EC50 values ranging around 30 nM. These results support the finding that p53 inactivation by Pft-alpha analogues could be also due to the presence of the cyclic dehydrated Pft-alpha forms, generated in situ in the biological assay incubation medium.

Ruminal fermentation and degradation patterns, protozoa population, and urinary purine derivatives excretion in goats and wethers fed diets based on two-stage olive cake: effect of PEG supply

Three experiments were conducted in Granadina goats and Segureña wethers fed at maintenance level to evaluate the effect of including a mixture of barley and a new by-product derived from olive oil extraction (two-stage dried olive cake) on ruminal degradation and passage kinetics (Exp. 1), fermentation pattern and protozoa population (Exp. 2), and urinary purine derivatives excretion (Exp. 3). Polyethylene glycol was supplied to the animals to evaluate the effects of tannins contained in the by-product. The experimental diets were as follows: alfalfa hay and alfalfa hay plus a concentrate, formulated with two-stage dried olive cake, barley, and a mineral-vitamin mixture either with or without the addition of polyethylene glycol to the drinking water. The inclusion of two-stage dried olive cake in the diet resulted in an increase of condensed tannins. Ruminal VFA concentration in goats and wethers increased (P < 0.05) and ammonia N (NH3-N) concentration decreased (P < 0.05). The inclusion of two-stage dried olive cake decreased (P < 0.001) urinary allantoin excretion only in wethers. Ruminal degradation profiles and fractional passage rates were similar in goats and wethers. The polyethylene glycol supply increased (P < 0.001) DM and N degradation rates in both animal species but did not modify the fractional passage rate. Ruminal fermentation patterns were also similar in goats and wethers and were affected by polyethylene glycol supply. In general, Entodiniomorphida and Holotricha protozoa counts were higher (P < 0.05) in the rumen of goats than of wethers. Protozoa count in wethers responded more to polyethylene glycol supply than in goats. The present work presents the first data obtained from a comparative study with sheep and goats concerning urinary excretion of purine derivatives. The excretion was similar in both animal species when fed alfalfa hay; however, polyethylene glycol affected only urinary allantoin excretion in wethers. Results suggest a greater sensitivity of wethers than of goats to two-stage olive cake condensed tannins.

Proapoptotic function of the MET tyrosine kinase receptor through caspase cleavage

The MET tyrosine kinase, the receptor of hepatocyte growth factor-scatter factor (HGF/SF), is known to be essential for normal development and cell survival. We report that stress stimuli induce the caspase-mediated cleavage of MET in physiological cellular targets, such as epithelial cells, embryonic hepatocytes, and cortical neurons. Cleavage occurs at aspartic residue 1000 within the SVD site of the juxtamembrane region, independently of the crucial docking tyrosine residues Y1001 or Y1347 and Y1354. This cleavage generates an intracellular 40-kDa MET fragment containing the kinase domain. The p40 MET fragment itself causes apoptosis of MDCK epithelial cells and embryonic cortical neurons, whereas its kinase-dead version is impaired in proapoptotic activity. Finally, HGF/SF treatment does not favor MET cleavage and apoptosis, confirming the known survival role of ligand-activated MET. Our results show that stress stimuli convert the MET survival receptor into a proapoptotic factor.

Ruminal fermentation and degradation patterns, protozoa population and urinary purine derivatives excretion in goats and wethers fed diets based on olive leaves1

Olives leaves, accrued during the processing of olive harvests for oil extraction, are poor in N, rich in crude fat and ADF (1.19, 8.03 and 28.2 g/100 g of DM, respectively), and relatively low in condensed tannins (11.1 mg/g of DM). Three experiments were conducted in a 2 x 3 (two animal species: goats vs. wethers; and three experimental diets: olive leaves without or with polyethylene glycol supply and olive leaves supplemented with barley and faba beans) factorial design to evaluate ruminal degradation and passage kinetics (Exp. 1), fermentation pattern and protozoa population (Exp. 2), and urinary purine derivatives excretion (Exp. 3). Polyethylene glycol was supplied to evaluate the effects of condensed tannins contained in olive leaves. Ruminal degradability of CP was low in both goats and wethers, although goats showed higher (P < 0.05) values than wethers. Supplementation of olive leaves with barley and faba beans increased (P < 0.001) ruminal degradability of DM and CP. Both goats and wethers fed olive leaves showed similarly low particulate fractional passage rates (0.021 and 0.023/h, respectively). Ingestion of olive leaves promoted low NH3-N and VFA concentrations, which reflect poor microbial activity. These concentrations, especially that of VFA, increased when barley and faba beans were added. Ingestion of olive leaves affected ruminal protozoa: Entodiniomorphida showed low concentrations and Holotricha completely disappeared. When animals received a diet based on olive leaves, barley, and faba beans, Holotricha appeared in the ruminal liquor and Entodiniomorphida increased (P < 0.001). In goats and wethers fed olive leaves alone, urinary allantoin excretion was very low (163 and 164 micromol/kg BW0.75 in goats and wethers, respectively), and moderate values (352 and 389 micromol/kg BW0.75 in goats and wethers, respectively) were observed when a diet of olive leaves, barley, and faba beans was fed. The polyethylene glycol supply did not have an effect in goats or in wethers, indicating the lack of an effect of condensed tannins in olive leaves. Ingestion of olive leaves promotes a low microbial activity, although its supplementation with readily degraded carbohydrates and protein improves microbial activity and, as a consequence, increases its ruminal degradation. In general, for most of the measured variables, there were no animal species x diet interactions. Thus, goats and wethers had similar ruminal activities when fed diets based on olive leaves.

The HIV-1 repeated sequence R as a robust hot-spot for copy-choice recombination

Template switching during reverse transcription is crucial for retroviral replication. While strand transfer on the terminal repeated sequence R is essential to achieve reverse transcription, template switching from internal regions of the genome (copy choice) leads to genetic recombination. We have developed an experimental system to study copy-choice recombination in vitro along the HIV-1 genome. We identify here several genomic regions, including the R sequence, where copy choice occurred at high rates. The frequency of copy choice occurring in a given region of template was strongly influenced by the surrounding sequences, an observation that suggests a pivotal role of the folding of template RNA in the process. The sequence R, instead, constituted an exception to this rule since it was a strong hot-spot for copy choice in the different sequence contexts tested. We suggest therefore that the structure of this region has been optimised during viral evolution to ensure efficient template switching independently from the sequences that might surround it.

Influence of phase duration of biphasic waveforms on defibrillation energy requirements with a 70-microF capacitance

BACKGROUND

Phase duration of biphasic shocks may be an important determinant of defibrillation success. The purpose of this study was to investigate the effect of changing phase duration of biphasic pulses delivered by 70-microF capacitors on defibrillation energy requirements. This may be clinically relevant for the optimization of implantable cardioverter-defibrillator design and programming.

METHODS AND RESULTS

Defibrillation thresholds (DFTs) were determined for 13 waveforms in 13 pigs by application of a 70-microF capacitance and a transvenous/submuscular lead system. In part I, phase-1 duration varied, preserving a phase-1/phase-2 duration ratio of 60%/40%. The phase-1 durations were 1, 2, 3, 4, 5, and 6 ms. The DFT was lowest (22.9+/-7 J) for phase 1=3 ms compared with phase 1=1 ms (36.4+/-7.5 J), 2 ms (25+/-6.5 J), 4 ms (25+/-7.6 J), 5 ms (30.7+/-7.3 J), or 6 ms (32.9+/-8.1 J) (P<.001). In part II, phase-1 duration was 3 ms but phase-2 duration varied: 0.7, 1.3, 2, 2.7, 3.3, 4, and 6 ms. Significant DFT minima were found at phase 2=2 ms (22.5+/-4.2 J) and phase 2=4 ms (22.5+/-4.2 J) compared with phase 2=0.7 ms (31.7+/-9.3 J), phase 2=3.3 ms (26.7+/-6.1 J), or phase 2=6 ms (28.3+/-6.8 J) (P<.05).

CONCLUSIONS

The strength-duration curve of biphasic defibrillation shocks demonstrates a single optimum for phase-1 duration. In contrast, two optima with minimal energy requirements were found for phase-2 duration. Optimization of both phases of low-capacitance biphasic shocks may reduce energy requirements for defibrillation.

Epidemiology of hydatidosis/echinococcosis in Ouarzazate, the pre-Saharian region of Morocco

In the Ouarzazate province of Southern Morocco, 1085 cattle and 358 sheep were examined for hydatid cysts. The prevalence was 44.6% (range 8.3-83.4%) in cattle and 5.3% (range 1.3-28.6%) in sheep. The prevalence increased with the age of the animals. The lung was the predominant site of infection, followed by the liver. In cattle, 14.2% of hydatid cysts were fertile and 16.4% had degenerative changes. The mean loss per head of cattle slaughtered was about 1 kg of liver and 900 g of lungs in the urban abattoirs. In monetary terms at the current price of 1980, this meant a loss of U.S. +4.5 at urban and +1.6 at rural abattoirs. The mean prevalence of infection in 61 stray dogs was 50.8%, with a mean worm burden of 413. The urban dogs had a lower infection rate (42.9%) than the rural dogs (61.5%). There were 130 dogs per 1000 inhabitants. The human population was ignorant of the life-cycle of Echinococcus granulosus and was not aware of risk of infection through dogs. Dogs become infected at abattoirs, at home slaughter and in the field by consuming dead carcasses. The maintenance and transmission of E. granulosus in animals and man is related to social, religious and cultural factors.