Leg ulcers in childhood: A multicenter study in France

BACKGROUND

Leg ulcers in adults are a major public health concern. Their incidence increases with age and many causes have been identified, predominantly associated with vascular diseases. Leg ulcers in children and teenagers are less frequent. The aim of our study was to identify the causes of leg ulcers in children and teenagers, and to evaluate their management.

METHODS

This retrospective multicenter study was conducted by members of the Angio-dermatology Group of the French Society of Dermatology and of the French Society of Pediatric Dermatology. Data from children and teenagers (< 18 years), seen between 2008 and 2020 in 12 French hospitals for chronic leg ulcer (disease course>4 weeks), were included.

RESULTS

We included 27 patients, aged from 2.3 to 17.0 years. The most frequent causes of leg ulcer were: general diseases (n=9: pyoderma gangrenosum, dermatomyositis, interferonopathy, sickle cell disease, prolidase deficiency, scleroderma, Ehlers-Danlos syndrome), vasculopathies (n=8: hemangioma, capillary malformation, arteriovenous malformation), trauma (n=4: bedsores, pressure ulcers under plaster cast), infectious diseases (n=4: pyoderma, tuberculosis, Buruli ulcer) and neuropathies (n=2). Comorbidities (59.3%) and chronic treatments (18.5%) identified as risk factors for delayed healing were frequent. The average time to healing was 9.1 months.

DISCUSSION

Leg ulcers are less frequent in children and teenagers than in adults and their causes differ from those in adults. Comorbidities associated with delayed healing must be identified and managed. Children and teenagers tend to heal faster than adults, but a multidisciplinary management approach is necessary.

Bringing high spatial resolution to the far-infrared: A giant leap for astrophysics

The far-infrared (FIR) regime is one of the wavelength ranges where no astronomical data with sub-arcsecond spatial resolution exist. None of the medium-term satellite projects like SPICA, Millimetron, or the Origins Space Telescope will resolve this malady. For many research areas, however, information at high spatial and spectral resolution in the FIR, taken from atomic fine-structure lines, from highly excited carbon monoxide (CO), light hydrides, and especially from water lines would open the door for transformative science. A main theme will be to trace the role of water in proto-planetary discs, to observationally advance our understanding of the planet formation process and, intimately related to that, the pathways to habitable planets and the emergence of life. Furthermore, key observations will zoom into the physics and chemistry of the star-formation process in our own Galaxy, as well as in external galaxies. The FIR provides unique tools to investigate in particular the energetics of heating, cooling, and shocks. The velocity-resolved data in these tracers will reveal the detailed dynamics engrained in these processes in a spatially resolved fashion, and will deliver the perfect synergy with ground-based molecular line data for the colder dense gas.

The GALAXIES inelastic hard X-ray scattering end-station at Synchrotron SOLEIL

GALAXIES is an in-vacuum undulator hard X-ray micro-focused beamline dedicated to the study of the electronic structure of materials with high energy resolution using both photoelectron spectroscopy and inelastic X-ray scattering and under both non-resonant (NR-IXS) and resonant (RIXS) conditions. Due to the penetrating power of hard X-rays and the `photon-in/photon-out' technique, the sample environment is not a limitation. Materials under extreme conditions, for example in diamond anvil cells or catalysis chambers, thus constitute a major research direction. Here, the design and performance of the inelastic X-ray scattering end-station that operates in the energy range from ∼4 keV up to 12 keV is reported, and its capabilities are highlighted using a selection of data taken from recently performed experiments. The ability to scan `on the fly' the incident and scattered/emitted X-ray energies, and the sample position enables fast data collection and high experimental throughput. A diamond X-ray transmission phase retarder, which can be used to generate circularly polarized light, will also be discussed in the light of the recent RIXS-MCD approach.

[Tracheobronchial prosthesis in Mounier-Kuhn syndrome: New perspectives]

INTRODUCTION

Mounier-Kuhn syndrome or tracheobronchomegaly is a rare congenital condition, the management of which is complex. We report the case of a patient who was treated with interventional endoscopy.

OBSERVATION

We describe the case of a 74-year-old man with a diagnosis of tracheobronchomegaly who was admitted in 2003 with a background of deteriorating respiratory status and the occurrence of postural syncope. He initially received a tracheobronchial silicone Y prosthesis, extended with metal prostheses at the tracheal and bronchial level. This arrangement remained stable until 2011. He then began to develop episodes of asphyxia related to posterior dislocation of the tracheobronchial prosthesis, after breakage of the metallic mesh tracheal prosthesis. A new tracheobronchial prosthesis Y was then placed, custom-made from a 3D model of the airways. This was clinically and functionally effective.

DISCUSSION

This case describes the management of a patient with Mounier-Kuhn syndrome by interventional bronchoscopy, with the adaptation of prosthetic materials, on an individual basis, to the anatomy of the patient's airway.

An animal model of amnesia that uses Receiver Operating Characteristics (ROC) analysis to distinguish recollection from familiarity deficits in recognition memory

Here we review our development of an animal model of episodic memory and amnesia that employs a signal detection analyses to characterize recognition memory performance in rats. This approach aims to distinguish episodic recollection of studied items from mere familiarity for recently experienced stimuli, and then to examine the neural basis of these memory processes. Our findings on intact animals indicate that it is possible to distinguish independent components of recognition that are associated with features of recollection and familiarity in humans. Furthermore, we have found that damage limited to the hippocampus results in a selective deficit in recollection and not familiarity. Also, aging and prefrontal damage result in a similar pattern of impaired recollection and spared familiarity. However, whereas the recollection deficit following hippocampal damage can be attributed to the forgetting of studied materials, the impairment following prefrontal damage is due to false alarms, likely reflecting a deficit in source monitoring.

Cancer incidence and mortality in France over the period 1978-2000

BACKGROUND

Monitoring cancer incidence and mortality time trends is essential for cancer research and health-care planning. French cancer registries do not cover the entire population and do not provide a representative sample of the national population. Our study aimed at estimating national cancer incidence and mortality trends over the longest period available.

METHODS

Incidence and mortality data were collected over the period 1978-1997. Twenty-seven cancer sites were selected and age, sex and site specific incidence and mortality rates were estimated for each year from 1978 up to 2000. Observed incidence and mortality data in the population covered by cancer registries were modelled using age-cohort methods. An estimation of the incidence/mortality ratio was obtained from these models and applied to the mortality rates predicted from an age-cohort model for the entire French population. The person-years of observation were calculated cohort-wise from census data provided by the national institute of statistics

RESULTS

Cancer incidence increased by 63% throughout the study period, from 170,000 new cases in 1980 to 278,000 in 2000. This evolution was due to demographic changes but also to an increase in the risk of cancer which was estimated to more than 35% during the same period. In men, this change is largely explain by the increase of prostate cancer incidence. Among women, the increase was dominated by the continuing increase in breast cancer incidence. Large increases were also seen for non-Hodgkin lymphoma, melanoma, and thyroid cancer in both genders and for lung cancer in women. Cancer mortality increased by 20% from 125,000 deaths in 1980 to 150,000 in 2000. This increase is less than that predicted from changes in demographic factors and corresponds in fact to a decrease in the risk of death estimated to about 8%, slightly greater for women than for men. This decrease is associated with a decreasing incidence for stomach cancers for both sexes, alcohol-related cancer for men and cervical cancer for women. Colo-rectal cancer decreasing mortality contributes to this improvement despite an incidence increase.

CONCLUSION

Between 1980 and 2000, the study showed a large change in the cancer burden both quantitatively and qualitatively. Decrease in exposure, earlier diagnosis and therapeutic improvement explained part of this change, but overall the distribution of cancer cases shifted toward a distribution including less aggressive cancers. A striking divergence between incidence and mortality trends is observed for a great number of cancers. Prostate cancer shares with breast cancer the same pattern of a severe increasing incidence and a stable mortality. This points to important changes in medical practice and needs further analysis. The trend of lung cancer mortality among women should be emphasised since the situation will inevitably worsen in the coming years. It is already the third cause of cancer death among women.

[Regulation of elastin synthesis]

Elastin is the main protein of elastic fibers and confers the property of elastic recoil to the tissues such as arteries, lung, elastic cartilage,... Elastin synthesis goes through several steps: gene transcription, alternative splicing of pre-mRNA, mRNA translation, hydroxylation of some proline residues of the newly synthesized protein-tropoelastin-, association of with a 67 kDa chaperone protein, secretion of tropoelastin molecules in the extracellular space, and their deposition on the microfibrillar scaffold which contains fibrillin 1, fibrillin 2, MAGP 1 and MAGP 2,.... After the synthesis of cross-links-lysinonorleucine, desmosine, isodesmosine-, elastin becomes insoluble and elastic. The elastogenic pathway is regulated at many levels. The most recently described regulatory mechanism of elastin synthesis is the control of elastin mRNA stability. Elastogenesis is well controlled during development and aging but remains responsive to external factors such as soluble compounds-cytokines, vitamins, hormones,...- and hemodynamic stress. In order to ensure its function, both quantity and quality of elastin should be and should remain optimal in elastic tissues.

Detection of corticotropin-releasing hormone receptor 1 immunoreactivity in cholinergic, dopaminergic and noradrenergic neurons of the murine basal forebrain and brainstem nuclei--potential implication for arousal and attention

Corticotropin-releasing hormone (CRH) interacts with noradrenergic, dopaminergic and cholinergic systems of the brain, and these interactions are thought to be of relevance for the stress response, anxiety-related behavior, and cognitive function. CRH mediates its central effects through two high-affinity membrane receptors, CRH receptor subtypes 1 and 2. It is however unclear at present whether cholinergic or catecholaminergic cells express these receptors themselves or whether the effects of CRH are indirectly mediated through interaction with other neurotransmitter systems. Therefore, this study investigated whether choline acetyltransferase immunoreactive neurons of the murine basal forebrain and brainstem nuclei, and tyrosine hydroxylase immunoreactive neurons located within the locus coeruleus, ventral tegmental area and substantia nigra co-express CRH receptor 1, employing a double-immunocytochemical procedure. Using an antibody against the C-terminus of the CRH type 1 receptor (CRH-R1), CRH-R1-like immunoreactivity was found in all cholinergic basal forebrain nuclei except the nucleus basalis magnocellularis. In particular, the diagonal band of Broca (vertical and horizontal limbs) showed a high degree of co-localization of CRH-R1 immunoreactivity and choline acetyltransferase immunoreactivity (both limbs >90%). A less intense immunoreactivity but still high rate of co-localization was detected in the cholinergic neurons of the medial septum (80%), while lowest co-localization was observed in choline acetyltransferase immunoreactive neurons of the substantia innominata (58%). An intermediate degree of co-localization (75%) was seen in the brainstem pedunculopontine tegmental nucleus, while the other major brainstem cholinergic nucleus, the laterodorsal tegmental nucleus, showed an even higher degree of choline acetyltransferase immunoreactivity-positive cells also immunoreactive for CRH-R1 (92%). All catecholaminergic structures studied displayed a pattern of CRH-R1 immunoreactivity strongly overlapping the pattern of tyrosine hydroxylase immunoreactivity. The intensity of the CRH-R1 signal was relatively low within the ventral tegmental area and the substantia nigra pars compacta, while the CRH-R1 signal was very intense and detected in almost all of the neurons of the locus coeruleus. These results clearly demonstrate that the cholinergic and catecholaminergic systems provide direct anatomical substrates for CRH action through the CRH-R1. These findings are of particular relevance for understanding the action of recently developed CRH-R1 antagonistic drugs which may offer a new therapeutic approach to treat stress-related disorders such as anxiety and depression and their concomitant alterations in arousal and cognitive functions.

[Assessing the quality of patients' medical records at the Claudius-Regaud Institute]

In 1999, the Claudius-Regaud Institute of Toulouse, France, specialized in oncology, set up a workshop in order to assess the quality of its patients medical records. A retrospective evaluation was performed on a 100-chart-sample drawn from all the charts in the institution. Results show that the medical records are subdivised into three parts: medical care, nursing care and imaging. Some of the explored charts show a lack of data, and a certain inconsistency in the charts' organization and in the structure of information was reported. Patient's record is a key to communication between the different care providers in oncology. To improve its quality, efforts will have to be done in restructuring the charts, creating guidelines and training the different caregivers.

Effects of the monoamine oxidase A inhibitor moclobemide on hippocampal plasticity in GR-impaired transgenic mice

A reduction in glucocorticoid receptor (GR) function leads to hippocampus-dependent allocentric spatial learning deficits, altered novelty exploration and disrupted hippocampal long-term potentiation (LTP) in transgenic mice expressing a GR antisense construct. After continuous long-term treatment of these mice with moclobemide (a reversible inhibitor of monoamine oxidase A), spatial navigation performance but not accuracy improved during initial acquisition. These changes were associated with a shift of the threshold for the induction of hippocampal LTP at low stimulation frequencies. Moreover, novel object exploration increased in both control and transgenic animals following long-term treatment with moclobemide. These findings open the possibility that antidepressants might improve hippocampal function under conditions of impaired stress hormone regulation, and that these drugs might in part act through this mechanism to attenuate cognitive deficiency in disorders such as depression.

Mild deficits in mice lacking pituitary adenylate cyclase-activating polypeptide receptor type 1 (PAC1) performing on memory tasks

Pituitary adenylate cyclase-activating polypeptide (PACAP) and its receptor subtype 1 (PAC1) have been suggested to play a role in the modulation of learning and memory. However, behavioral evidence for altered mnemonic function due to altered PAC1 activity is missing. Therefore, the role of PAC1 in learning and memory was studied in mouse mutants lacking this receptor (PAC1 knock-out mice), tested in water maze two-choice spatial discrimination, one-trial contextual and cued fear conditioning, and multiple-session contextual discrimination. Water maze spatial discrimination was unaffected in PAC1 mutants, while a mild deficit was observed in multiple session contextual discrimination in PAC1 knock-out mice. Furthermore, PAC1 knock-out mice were able to learn the association between context and shock in one-trial contextual conditioning, but showed faster return to baseline than wild-type mice. Thus, the effects of PAC1 knock-out on modulating performance in these tasks were subtle and suggest that PAC1 only plays a limited role in learning and memory.

Glucocorticoid receptor impairment enhances impulsive responding in transgenic mice performing on a simultaneous visual discrimination task

Transgenic mice with impaired glucocorticoid receptor (GR) function were tested for their ability to learn and perform a series of simultaneous visual discriminations which allowed a dissociation between accuracy of discrimination from those of motivation and behavioural disinhibition. Animals were first trained on an operant five-choice simultaneous discrimination autoshaping procedure, followed by a continuous reinforcement schedule on that task. Subsequently, the number of choices was limited to two and data were analysed according to the mathematical methods of signal detection theory (SDT). The effects of GR-antisense expression on accuracy when different rates of responding were required were studied under different fixed ratio response requirements (FR1-FR10). Autoshaping was retarded in transgenic animals and accuracy was impaired in both the five-choice and the two-choice discrimination tasks, although transgenic mice showed clear evidence for learning. Under conditions of low response requirements, transgenic mice showed increased response and cognitive biases, but reduced perceptual bias, and a behavioural disinhibition, characterized by a reduction in errors of omission, decreased response latencies and increased number of responses during the inter-trial interval. Increasing the response requirement improved performance in transgenic animals as reflected by enhanced accuracy. Moreover, transgenics were less susceptible to the deleterious effects of higher response requirements, as indicated by relatively unaffected bias measures in this group, while bias increased in controls. These results indicate that altered performance in GR-antisense transgenic animals cannot simply be interpreted as a mnemonic deficit, but that altered motivation and enhanced impulsive responding may account for some of these impairments.

Insulin stimulates NHE1 activity by sequential activation of phosphatidylinositol 3-kinase and protein kinase C zeta in human erythrocytes

The signaling cascade linking insulin receptor stimulation to the activation of Na/H exchanger (NHE) was investigated in human erythrocytes, a simple cell model expressing the NHE1 isoform and protein kinase C (PKC) alpha and zeta isoforms only. Our results demonstrate the presence of phosphatidylinositol (PtdIns) 3-kinase in these cells and its activation by insulin. With a similar time-course, insulin also promoted both the translocation and activation of PKC zeta, but had no effect on PKC alpha. Inhibition of PtdIns 3-kinase with wortmannin prevented the activation of PKC zeta by insulin. Stimulation of NHE1 was observed after 10 min of insulin treatment and persisted for at least 60 min. This effect was totally abolished by wortmannin or GF 109203X, an inhibitor of all PKC isoforms, but not by Gö 6976, a specific inhibitor of conventional and novel PKCs (e.g. PKC alpha). These data indicate that PKC zeta activation is mediated by a PtdIns 3-kinase-dependent mechanism and that NHE1 stimulation involves the sequential activation of PtdIns 3-kinase and PKC zeta. In addition, insulin stimulation of NHE1 occurred without altering the phosphorylation state of the exchanger, suggesting that the phosphorylation of an ancillary protein by PKC zeta would be responsible for activation of the transporter.

[A study based on national DRG data to evaluate work load and practice relating to cancer patients in not-for-profit hospitals]

BACKGROUND

In France there is no reliable information describing the organisation of hospital care for patients with cancer. The present study attempts to clarify this issue taking advantage of an information source that has up to now been unused, namely the national PMSI (Information System Medical program) data base.

METHODS

A quantitative study has been carried out regarding cancer management in France using information filed with the PMSI which compiles data related to hospital admissions in all institutions with more than 100 beds and subject to a defined global budget. The "cancer" component of hospital activity was extracted using a specific algorithm which utilized the diagnostic and intervention codes included in the admission summaries. By using the unit of activity as defined by the ISA (Activity Synthetic Index) and the scale of relative cost according to the GHM (Homogeneous Group of patients) it was possible to analyse the information in terms of a balance sheet.

RESULTS

The study provided information regarding the costs and methods of management, including therapeutic strategies, for each type of hospital establishment. It is shown that with one death out of six, cancer covers a quarter of all hospital stays, and one sixth of annual hospital expenses. This accounts for 16.2% of ISA ie approximately 29 billion francs (4.6 billion dollars) for the public and semipublic sectors. Surgery, which accounted for 32% of expenditures, appeared to be the most expensive intervention, ahead of chemotherapy (16.3%) and radiotherapy (9.1%). Each type of hospital organisation (university, cancer centre, district hospital) had their own relative figures.

CONCLUSION

Through this study the current situation regarding cancer care in hospital has been documented. It has also demonstrated the value of the PMSI data base as a source of information for large scale quantitative studies of health care economics. However, the PMSI does not yet provide details regarding infrastructure or succession of hospital stay. Ultimately, this analysis does not provide any information on the quality or efficacy of care but does define a typological system for health care organisations which could provide information on distribution of resources.

Excitotoxic hippocampal lesions disrupt allocentric spatial learning in mice: effects of strain and task demands

Spatial discrimination of ibotenic acid-lesioned C57BL/6 (B6) and DBA/2 (D2) mice was tested in two-choice water maze and plus maze tasks. B6 but not D2 mice learned the spatial discrimination in the water maze, but strains did not differ in learning a spatial discrimination in the plus maze paradigm. Ibotenic acid lesions of the hippocampus impaired percentage correct choices in the water maze spatial discrimination task in B6 but not in D2 mice, the latter of which may have been due to a floor effect. Furthermore, lesioned mice were more thigmotaxic, the distance travelled until a choice was made was longer and animals made more errors of omission. Despite the poor performance during water maze acquisition, lesioned animals, as well as sham-lesioned D2 mice, eventually acquired some place response in the water maze, as was evident when the location of the platform was reversed. However, hippocampus-lesioned mice of both strains were impaired when tested in the plus maze spatial discrimination task. Thus, ibotenic acid-induced lesions of the hippocampus impair acquisition of spatial discrimination in mice. These deficits were strain-dependent and likely comprise impaired accuracy as well as changes in non-mnemonic types of behaviour. Importantly, lesions in both strains impaired spatial learning, and whether a deficit was seen in mice of the D2 strain seemed to depend on the demands of the task.

Influence of elastin gene polymorphism on the elastin content of the aorta: A study in 2 strains of rat

The elastin content in the thoracic aorta of male Brown-Norway (BN) rats is 31.4+/-1.2% (dry weight), whereas that of male LOU rats is 37.2+/-1.0%. A similar difference in the elastin content of the thoracic aorta is also observed in female animals. Furthermore, in the thoracic aorta of young, growing rats as well as in cultured aortic smooth muscle cells, the steady-state level of elastin mRNA is significantly lower in the BN than in the LOU strain. These results suggested that 1 or more genes control the elastin mRNA level and the elastin content in the aortas of BN and LOU rats. A possible relationship between a polymorphism in the elastin gene and the elastin content of the aorta was tested. For this purpose, the aortic elastin content was measured in F(1) and F(2) generations bred from LOU and BN rats and was compared with that of the F(0) (parental) generation. A polymorphic marker located in intron 25 of the elastin gene has been used to genotype the F(2) rats. The degree of genetic determination of aortic elastin content was estimated to be 73% in the F(2) cohort, but the elastin locus accounts for only 3. 9% of the total variance in aortic elastin content. Other genes are thus responsible for the major part of the observed interstrain difference by regulating the transcription of the gene, the stability of elastin mRNA, and/or posttranslational events.

Disrupted allocentric but preserved egocentric spatial learning in transgenic mice with impaired glucocorticoid receptor function

Spatial and non-spatial learning of mice with an incorporated antisense RNA complementary to a fragment of cDNA coding for the glucocorticoid receptor (GR) were evaluated in allocentric and egocentric radial maze and water maze tasks, and in spontaneous object recognition and sensorimotor learning paradigms. Mice with impaired GR function did not acquire two maze paradigms based on allocentric spatial navigation, radial maze non-matching to position and water maze spatial discrimination learning. Comparison of performance in spaced and massed trials indicated that this may be due to a general inability to store information into allocentric reference memory or in retrieval processes. However, both groups of animals learned the rules of an egocentric radial maze task at similar rates and there was no difference in their ability to recognise objects once animals had equal opportunity to explore the sample objects. Sensorimotor performance was impaired in transgenic animals, but it is suggested that this is due to non-specific factors rather than to disrupted sensorimotor learning per se. These results are consistent with a disruption of hippocampal function. Histological examination of the hippocampus revealed no obvious structural abnormalities in transgenic animals. Therefore, the data suggest that functional underactivity of GRs at the level of the hippocampus induces a deficit in allocentric navigation while sparing egocentric navigation and object recognition.

Involvement of deoxygenation-induced increase in tyrosine kinase activity in sickle cell dehydration

Deoxygenation of sickle (SS) cells causes cationic alterations leading to cell dehydration by various mechanisms, including activation of Ca2+-sensitive K channels and possibly of K-Cl cotransport. Since an abnormal tyrosine kinase (TK) activity exists in SS cells we investigated the possible role of tyrosine phosphorylation in SS cell dehydration. In density-fractionated SS reticulocytes and discocytes, but not in normal red cells, deoxygenation increased membrane and cytosolic TK activities and tyrosine phosphorylation of band 3, independently of external Ca2+. These effects were abolished by the TK inhibitors methyl 2, 5-dihydroxycinnamate (DiOH) or tyrphostin 47 (T47). Deoxygenation-induced Ca2+ uptake was not affected by the inhibitors and Na+ gain was reduced by T47 and not by DiOH. Both inhibitors decreased the loss of K+ and cellular dehydration. The effect of the inhibitors on K+ efflux was still observed in the absence of external Ca2+. These data indicate that the TK inhibitors do not interfere with deoxygenation-induced membrane permeabilization, but affect Ca2+-independent K+ efflux. It cannot be excluded, however, that the TK inhibitors also attenuate Ca2+-sensitive K+ efflux. Based on recent evidence from the literature, it is suggested that the diminution of K+ efflux results in part from inhibition of K-Cl cotransport activity.

Localization of elastin mRNA and TGF-beta1 in rat aorta and caudal artery as a function of age

Several in vitro studies have previously demonstrated that the addition of TGF-beta to aortic smooth muscle cells or skin fibroblasts stimulates elastin synthesis. It is not clear however whether, in vivo, TGF-beta participates in the regulation of elastin synthesis, especially in physiological conditions. The aim of our study was to explore the localization of elastin mRNA and TGF-beta1 in the rat thoracic aorta (an elastic artery) and caudal artery (a muscular artery). Elastin mRNA was localized by in situ hybridization and quantified using Northern blot analysis. TGF-beta1 was detected using immunohistochemistry. The study was carried out as a function of age (rats of 3, 10, 20, and 30 months). We observed that TGF-beta1 immunoreactivity is present predominantly, but not exclusively, at the sites of elastin synthesis as determined by elastin mRNA detection: in smooth muscle cells in the aorta and in endothelial cells in the caudal artery. The ability of exogenously added TGF-beta1 (0.001-10 ng/ml) to modulate the steady-state levels of elastin mRNA in primary cultures of endothelial cells, smooth muscle cells, and fibroblasts isolated from the thoracic aorta was also studied. At the highest concentration used, elastin mRNA levels increased 5-fold in endothelial cells and 11-fold in smooth muscle cells. The demonstration that TGF-beta1 immunoreactivity is present at the sites of elastin synthesis in the thoracic aorta and in the caudal artery and the observation that TGF-beta1 induces an increase in elastin mRNA levels in cultured endothelial cells and smooth muscle cells suggest that TGF-beta1 may be implicated, at least in part, in the physiological regulation of elastin gene expression.

Effects of PKC alpha activation on Ca2+ pump and K(Ca) channel in deoxygenated sickle cells

We have previously shown that a pretreatment with phorbol 12-myristate 13-acetate (PMA), an activator of protein kinase C (PKC), reduced deoxygenation-induced K+ loss and Ca2+ uptake and prevented cell dehydration in sickle anemia red blood cells (SS cells) (H. Fathallah, E. Coezy, R.-S. De Neef, M.-D. Hardy-Dessources, and F. Giraud. Blood 86: 1999-2007, 1995). The present study explores the detailed mechanism of this PMA-induced inhibition. The main findings are, first, the detection of PKC alpha and PKC zeta in normal red blood cells and the demonstration that both isoforms are expressed at higher levels in SS cells. The alpha-isoform only is translocated to the membrane and activated by PMA and by elevation of cytosolic Ca2+. Second, PMA is demonstrated to activate Ca2+ efflux in deoxygenated SS cells by a direct stimulation of the Ca2+ pump. PMA, moreover, inhibits deoxygenation-induced, charybdotoxin-sensitive K+ efflux in SS cells. This inhibition is partly indirect and explained by the reduced deoxygenation-induced rise in cytosolic Ca2+ resulting from Ca2+ pump stimulation. However, a significant inhibition of the Ca2+-activated K+ channels (K(Ca) channels) by PMA can also be demonstrated when the channels are activated by Ca2+ plus ionophore, under conditions in which the Ca2+ pump is operating near its maximal extrusion rate, but swamped by Ca2+ plus ionophore. The data thus suggest a PKC alpha-mediated phosphorylation both of the Ca2+ pump and of the K(Ca) channel or an auxiliary protein.

Expression of c-fos in bulbar nuclei involved in cardiovascular control following the electrical stimulation of sensorimotor cortex in the rat

Previous studies have shown that electrical stimulation of the sensorimotor cortex (SMC) induces responses of the autonomic nervous system such as variations in heart rate and arterial pressure. Neuroanatomical studies have shown the existence of monosynaptic projections from the SMC to the nucleus tractus solitarius (NTS), the rostral ventrolateral medulla (RVLM) and the dorsal nucleus of the vagus nerve (DNV), which are bulbar nuclei involved in cardiovascular control. The aim of the present study was to establish whether there exists a functional connectivity between the SMC and these nuclei. Electrical stimulation applied to the SMC of 7 rats for 1 h induced the expression of c-fos-protein-like immunoreactivity in the nucleus of some neurons in NTS, RVLM and DNV. These data support the view that the SMC has functional connections with bulbar neurons involved in cardiovascular control.

Aortic elastin and collagen content and synthesis in two strains of rats with different susceptibilities to rupture of the internal elastic lamina

We have previously characterized two normotensive strains of rats which differ markedly in their susceptibility to spontaneous rupture of the internal elastic lamina (IEL), the Brown Norway (BN) being very susceptible and the Long Evans (LE) being resistant. Here we quantified biochemically the elastin and collagen content of aortae from adult male BN and LE rats aged 12, 18 and 22 weeks and showed that the elastin content was lower and the collagen content higher in the BN strain than in the LE strain, resulting in a markedly lower elastin/collagen ratio in the former strain. These modifications were present both in the thoracic aorta, which is devoid of IEL ruptures, and in the abdominal segment where ruptures frequently occur in the BN rat, suggesting that they could represent a predisposing factor in the presence of other local factors. Quantifications of relevant mRNAs in aortae of younger male BN and LE rats by Northern blot showed that there are lower tropoelastin transcript levels in the BN rat at 6 weeks in both thoracic and abdominal segments than in the age-matched LE rat. In contrast there was no consistent interstrain difference in alpha 1 type I collagen transcripts and alpha 1 type III collagen transcripts were higher in the BN aorta only at 6 weeks in the abdominal segment. We conclude that the BN rat presents an aortic elastin deficit which appears to be in part explained by a decreased elastin synthesis in young, growing rats and may be genetically determined. However, a direct relation of this elastin deficit with susceptibility to rupture of the IEL cannot be concluded from this study.

Characterization of structural and functional phosphoinositide domains in human erythrocyte membranes

In the erythrocyte membrane, only a fraction (50-60%) of phosphatidylinositol 4,5-bisphosphate (PIP2) and of phosphatidylinositol 4-phosphate (PIP) is rapidly turned over by specific kinases and phosphatases and accessible to hydrolysis by the polyphosphoinositide (PPI)-specific phospholipase C (PLC). To investigate whether the metabolic segregation of PPI resulted from preferential interactions with proteins, we have measured the accessibility of PPI to bee venom phospholipase A2 (PLA2) in native erythrocyte membranes, or after treatments designed to remove peripheral proteins and cytoplasmic domains of integral proteins. In native membranes, PPI, as well as the other major phospholipids, behaved as two distinct fractions (R1 and R2) differing by their sensitivity to PLA2. Such a behavior was not observed in PIP and PIP2 containing artificial vesicles. Evidence was provided that the highly sensitive fraction of PIP and PIP2 (R1) may be identical to the PLC-sensitive and rapidly metabolized pool. Removal of peripheral proteins, followed by proteolysis of the cytoplasmic domain of integral proteins, mainly glycophorins and band 3, led to a reduction of the R1 fraction of PIP and of PIP2. It is proposed that the rapidly metabolized pool of PIP2 and PIP, involved in the regulation of major cellular functions, would be maintained in its functional state through interactions with integral proteins.

Asymmetric distribution of phosphoinositides and phosphatidic acid in the human erythrocyte membrane

The distribution of phosphoinositides and phosphatidic acid (PA) between the outer and inner layers of the human erythrocyte membrane was investigated by using two complementary methodologies: hydrolysis by phospholipase A2 (PLA2) and immunofluorescence detection with monoclonal antibodies against polyphosphoinositides. The contents of phosphatidylinositol 4,5-bisphosphate (PIP2), phosphatidylinositol 4-phosphate (PIP) and PA were decreased by 15-20% after 60 min incubation with PLA2, while that of phosphatidylinositol (PI) was increased. Studies with 32P-labelled cells revealed that PLA2 treatment led to indirect effects on the metabolism of these phospholipids. Therefore, the asymmetric distribution of phosphoinositides and PA was inferred from the data obtained in ATP-depleted erythrocytes. In these cells with arrested phosphoinositide metabolism, the asymmetric distribution of the major phospholipids was maintained: PLA2 hydrolyzed approx. 20% of PI, PIP2 and PA (but no PIP) indicating their localization in the outer layer of the membrane. This finding was confirmed by immunofluorescence studies with antibodies specific to each phosphoinositide. External addition of anti-PIP2 but not anti-PIP gave a positive reaction both in control and in ATP-depleted erythrocytes. A pretreatment of cells with PLA2 led to a decrease in the intensity of anti-PIP2 staining. These results demonstrate that significant fractions of PIP2, PI and PA are localized on the outer surface of the erythrocyte membrane.

Turnover of [14C] sucrose HDL and uptake by organs in the normal or genetically hypercholesterolemic (RICO) rat using a constant infusion method

The turnover and tissular uptake of HDL (d 1.095-1.21) have been compared in normocholesterolemic or genetically hypercholesterolemic rats by a constant infusion method of [14C] sucrose labelled HDL for 8 h. The HDL clearance rate was not significantly smaller in the RICO than in the normocholesterolemic animal (320 +/- 22 microliters.h-1 versus 366 +/- 24 microliters.h-1 per 100 g of rat). It was the same case for the fractional catabolic rate, respectively equal to 7.8 and 9.4 +/- 0.6%.h-1. For both strains, liver and skeletal muscle were the main catabolic sites for HDL. The HDL uptake rates in intestine or kidney were 3-4-fold smaller than those in the liver. In the RICO rat, intestine, testis and adrenals showed a lesser HDL uptake capacity (expressed per g of organ) than the normocholesterolemic rat.

[Efficacy of a new antisecretory agent (40 749 RP) on human gastric secretion induced by a meal (intragastric titration)]

An antisecretory drug of a new series, 40 749 RP, without anticholinergic or H2 receptor antagonist activities, was tested on meal-induced gastric acid secretion in 6 healthy volunteers. Gastric acid secretion and emptying of liquid were measured using intragastric titration. Oral dosages tested were 1, 2 and 4 mg/kg versus placebo. Inhibitions obtained were dose-related and expressed in percentage of the placebo values: 36 +/- 10 p. 100 for 1 mg/kg; 51 +/- 13 p. 100 for 2 mg/kg and 83 +/- 5 p. 100 for 4 mg/kg. Statistically significant correlation (p less than 0.001) was observed between maximal blood concentration of 40 749 RP and the percentage of secretory inhibition during the 90 min of the test. No change in gastrin response or in gastric emptying was observed whatever the dose.

Rotatory power measurements in the X-ray range with synchrotron radiation: Experimental set-up and preliminary results for NaBrO3 single crystals

The specific rotation of NaBrO3 single crystals has been measured with an X-ray beam extracted from the white synchrotron radiation spectrum by a specially designed silicon monochromator–polarizer. A detailed description of the monochromator principle and expected performance is given and the characteristics of the output beam are as follows: extremely narrow angular and wavelength spread (Δθ = 7 μrad, Δλ = 8 × 10–6 Å), nearly pure linear polarization (polarization ratio 2.5 × 108). The wavelength has been chosen very close to the bromine K edge (λ − λ K = 2 × 10–3 Å) in order to take advantage of possible resonant effects. The experimental set-up is of the crossed-polarizer type, the analyzer being a GaAs crystal adjusted for the 555 reflection with a Bragg angle θA equal to 44.95°. The specific rotation measured in these conditions has been found to be 0.35 ± 0.31° cm−1. An explanation is proposed for this small value.

Ranitidine upon meal-induced gastric secretion: oral pharmacokinetics and plasma concentration effect relationships

1 Ranitidine oral kinetics and plasma concentration-effect relationships upon meal-induced gastric secretion were investigated in normal subjects. Four oral doses of ranitidine (50, 100, 150 or 200 mg) and placebo were tested. 2 Oral ranitidine showed a terminal half-life of about 2 h 25 min. Maximal plasma level was about 240 ng/ml for a 100 mg dose, and occurred about 1 h after dose. From the range of 50 to 200 mg dose, no indication of non-linearity was observed in the drug kinetics. 3 Ranitidine administration resulted in a dose-related reduction in meal-stimulated acid secretion reaching, 46, 70, 82 and 92%, respectively. Mean ranitidine plasma concentrations producing 50 and 80% inhibition of acid secretion were 73 and 180 ng/ml, respectively, with great inter-individual variability. 150 and 200 mg ranitidine oral doses maintained IC50 for at least 4.5 and 5.5 h, respectively. Upon oral administration, ranitidine exerted no effect on gastric emptying of the meal but slightly decreased the gastrin response to the meal.