Preliminary insights into RNA in CSF of pediatric SMA patients after 6 months of nusinersen

BACKGROUND

Spinal muscular atrophy (SMA) is a rare autosomal-recessive neurodegenerative disorder caused by mutations in survival motor neuron 1 (SMN1) gene, and consequent loss of function of SMN protein, which results in progressive loss of lower motor neurons, and muscular wasting. Antisense oligonucleotide (ASO) nusinersen (Spinraza®) modulates the pre-mRNA splicing of the SMN2 gene, allowing rebalance of biologically active SMN. It is administered intrathecally via lumbar puncture after removing an equal amount of cerebrospinal fluid (CSF). Its effect was proven beneficial and approved since 2017 for SMA treatment. Given the direct effect of nusinersen on RNA metabolism, the aim of this project was to evaluate cell-free RNA (cfRNA) in CSF of SMA patients under ASOs treatment for biomarker discovery.

METHODS

By RNA-sequencing approach, RNA obtained from CSF of pediatric SMA type 2 and 3 patients was processed after 6 months of nusinersen treatment, at fifth intrathecal injection (T6), and compared to baseline (T0).

RESULTS

We observed the deregulation of cfRNAs in patients at T6 and we were able to classify these RNAs into disease specific, treatment specific and treatment dependent. Moreover, we subdivided patients into "homogeneous" and "heterogeneous" according to their gene expression pattern. The "heterogeneous" group showed peculiar activation of genes coding for ribosomal components, meaning that in these patients a different molecular effect of nusinersen is observable, even if this specific molecular response was not referable to a clinical pattern.

CONCLUSIONS

This study provides preliminary insights into modulation of gene expression dependent on nusinersen treatment and lays the foundation for biomarkers discovery.

Age-related differences in bottom-up and top-down attention: Insights from EEG and MEG

Attention operates through top‐down and bottom‐up processes, and a balance between these processes is crucial for daily tasks. Imperilling such balance could explain ageing‐associated attentional problems such as exacerbated distractibility. In this study, we aimed to characterize this enhanced distractibility by investigating the impact of ageing upon event‐related components associated with top‐down and bottom‐up attentional processes. MEG and EEG data were acquired from 14 older and 14 younger healthy adults while performing a task that conjointly evaluates top‐down and bottom‐up attention. Event‐related components were analysed on sensor and source levels. In comparison with the younger group, the older mainly displayed (1) reduced target anticipation processes (reduced CMV), (2) increased early target processing (larger P50 but smaller N1) and (3) increased processing of early distracting sounds (larger N1 but reduced P3a), followed by a (4) prolonged reorientation towards the main task (larger RON). Taken together, our results suggest that the enhanced distractibility in ageing could stem from top‐down deficits, in particular from reduced inhibitory and reorientation processes.

High Dream Recall Frequency Is Associated with an Increase of Both Bottom-Up and Top-Down Attentional Processes

Event-related potentials (ERPs) associated with the involuntary orientation of (bottom-up) attention toward an unexpected sound are of larger amplitude in high dream recallers (HR) than in low dream recallers (LR) during passive listening, suggesting different attentional functioning. We measured bottom-up and top-down attentional performance and their cerebral correlates in 18 HR (11 women, age = 22.7 years, dream recall frequency = 5.3 days with a dream recall per week) and 19 LR (10 women, age = 22.3, DRF = 0.2) using EEG and the Competitive Attention Task. Between-group differences were found in ERPs but not in behavior. The results show that HR present larger ERPs to distracting sounds than LR even during active listening, arguing for enhanced bottom-up processing of irrelevant sounds. HR also presented larger contingent negative variation during target expectancy and P3b to target sounds than LR, speaking for an enhanced recruitment of top-down attention. The attentional balance seems preserved in HR since their performances are not altered, but possibly at a higher resource cost. In HR, increased bottom-up processes would favor dream recall through awakening facilitation during sleep and enhanced top-down processes may foster dream recall through increased awareness and/or short-term memory stability of dream content.

What's in Your Gamma? Activation of the Ventral Fronto-Parietal Attentional Network in Response to Distracting Sounds

Auditory attention operates through top-down (TD) and bottom-up (BU) mechanisms that are supported by dorsal and ventral brain networks, respectively, with the main overlap in the lateral prefrontal cortex (lPFC). A good TD/BU balance is essential to be both task-efficient and aware of our environment, yet it is rarely investigated. Oscillatory activity is a novel method to probe the attentional dynamics with evidence that gamma activity (>30 Hz) could signal BU processing and thus would be a good candidate to support the activation of the ventral BU attention network. Magnetoencephalography data were collected from 21 young adults performing the competitive attention task, which enables simultaneous investigation of BU and TD attentional mechanisms. Distracting sounds elicited an increase in gamma activity in regions of the BU ventral network. TD attention modulated these gamma responses in regions of the inhibitory cognitive control system: the medial prefrontal and anterior cingulate cortices. Finally, distracting-sound-induced gamma activity was synchronous between the auditory cortices and several distant brain regions, notably the lPFC. We provide novel insight into the role of gamma activity 1) in supporting the activation of the ventral BU attention network and 2) in subtending the TD/BU attention balance in the PFC.

Is Migraine Associated to Brain Anatomical Alterations? New Data and Coordinate-Based Meta-analysis

A growing number of studies investigate brain anatomy in migraine using voxel- (VBM) and surface-based morphometry (SBM), as well as diffusion tensor imaging (DTI). The purpose of this article is to identify consistent patterns of anatomical alterations associated with migraine. First, 19 migraineurs without aura and 19 healthy participants were included in a brain imaging study. T1-weighted MRIs and DTI sequences were acquired and analyzed using VBM, SBM and tract-based spatial statistics. No significant alterations of gray matter (GM) volume, cortical thickness, cortical gyrification, sulcus depth and white-matter tract integrity could be observed. However, migraineurs displayed decreased white matter (WM) volume in the left superior longitudinal fasciculus. Second, a systematic review of the literature employing VBM, SBM and DTI was conducted to investigate brain anatomy in migraine. Meta-analysis was performed using Seed-based d Mapping via permutation of subject images (SDM-PSI) on GM volume, WM volume and cortical thickness data. Alterations of GM volume, WM volume, cortical thickness or white-matter tract integrity were reported in 72%, 50%, 56% and 33% of published studies respectively. Spatial distribution and direction of the disclosed effects were highly inconsistent across studies. The SDM-PSI analysis revealed neither significant decrease nor significant increase of GM volume, WM volume or cortical thickness in migraine. Overall there is to this day no strong evidence of specific brain anatomical alterations reliably associated to migraine. Possible explanations of this conflicting literature are discussed. Trial registration number: NCT02791997, registrated February 6th, 2015.

Auditory attention alterations in migraine: A behavioral and MEG/EEG study

OBJECTIVES

To evaluate alterations of top-down and/or bottom-up attention in migraine and their cortical underpinnings.

METHODS

19 migraineurs between attacks and 19 matched control participants performed a task evaluating jointly top-down and bottom-up attention, using visually-cued target sounds and unexpected task-irrelevant distracting sounds. Behavioral responses and magneto- and electro-encephalography signals were recorded. Event-related potentials and fields were processed and source reconstruction was applied to event-related fields.

RESULTS

At the behavioral level, neither top-down nor bottom-up attentional processes appeared to be altered in migraine. However, migraineurs presented heightened evoked responses following distracting sounds (orienting component of the N1 and Re-Orienting Negativity, RON) and following target sounds (orienting component of the N1), concomitant to an increased recruitment of the right temporo-parietal junction. They also displayed an increased effect of the cue informational value on target processing resulting in the elicitation of a negative difference (Nd).

CONCLUSIONS

Migraineurs appear to display increased bottom-up orienting response to all incoming sounds, and an enhanced recruitment of top-down attention.

SIGNIFICANCE

The interictal state in migraine is characterized by an exacerbation of the orienting response to attended and unattended sounds. These attentional alterations might participate to the peculiar vulnerability of the migraine brain to all incoming stimuli.

Self-perceived attention difficulties are associated with sensory hypersensitivity in migraine

BACKGROUND

Attention is the process which enables to preferentially select salient or relevant stimuli and to attenuate the response to irrelevant incoming stimuli. Migraine is characterized by both attentional alterations and an abnormal sensory processing to external stimulations. The aim of the study was to investigate potential interactions between self-perceived attentional difficulties and sensory hypersensitivity in migraine patients.

METHODS

Forty-six episodic migraineurs without aura and 46 healthy controls filled out questionnaires on self-perceived attention difficulties and self-reported sensitivity to visual, auditory and olfactory stimulations.

RESULTS

Compared to controls, migraineurs reported significantly higher levels of attention difficulty and sensory sensitivity. Sensory hypersensitivity correlated significantly with self-perceived attentional difficulties in migraineurs (P=0.002), but not with migraine disability or levels of anxiety or depression. Ictal and interictal sensory sensitivities were significantly correlated in migraineurs within visual (P<0.001), auditory (P<0.001) and olfactory (P=0.001) modalities.

CONCLUSION

This study shows for the first time an association between self-reported attentional difficulties and multimodal sensory hypersensitivity. Studies combining behavioral and physiological measures of sensory processing and attention processes are necessary to further understand the peculiar vulnerability of migraineurs to sensory stimuli.

Age-related modulations of alpha and gamma brain activities underlying anticipation and distraction

Attention operates through top-down (TD) and bottom-up (BU) mechanisms. Recently, it has been shown that slow (alpha) frequencies index facilitatory and suppressive mechanisms of TD attention and faster (gamma) frequencies signal BU attentional capture. Ageing is characterized by increased behavioral distractibility, resulting from either a reduced efficiency of TD attention or an enhanced triggering of BU attention. However, only few studies have investigated the impact of ageing upon the oscillatory activities involved in TD and BU attention. MEG data were collected from 14 elderly and 14 matched young healthy human participants while performing the Competitive Attention Task. Elderly participants displayed (1) exacerbated behavioral distractibility, (2) altered TD suppressive mechanisms, indexed by a reduced alpha synchronization in task-irrelevant regions, (3) less prominent alpha peak-frequency differences between cortical regions, (4) a similar BU system activation indexed by gamma activity, and (5) a reduced activation of lateral prefrontal inhibitory control regions. These results show that the ageing-related increased distractibility is of TD origin.

Fronto-central P3a to distracting sounds: An index of their arousing properties

The P3a observed after novel events is an event-related potential comprising an early fronto-central phase and a late fronto-parietal phase. It has classically been considered to reflect the attention processing of distracting stimuli. However, novel sounds can lead to behavioral facilitation as much as behavioral distraction. This illustrates the duality of the orienting response which includes both an attentional and an arousal component. Using a paradigm with visual or auditory targets to detect and irrelevant unexpected distracting sounds to ignore, we showed that the facilitation effect by distracting sounds is independent of the target modality and endures more than 1500 ms. These results confirm that the behavioral facilitation observed after distracting sounds is related to an increase in unspecific phasic arousal on top of the attentional capture. Moreover, the amplitude of the early phase of the P3a to distracting sounds positively correlated with subjective arousal ratings, contrary to other event-related potentials. We propose that the fronto-central early phase of the P3a would index the arousing properties of distracting sounds and would be linked to the arousal component of the orienting response. Finally, we discuss the relevance of the P3a as a marker of distraction.

[Pediatric cases in preclinical emergency medicine: critical aspects in the range of missions covered by ground ambulance and air rescue services]

BACKGROUND

The aim of this study was to demonstrate differences in structure and severity of pediatric emergencies treated by aeromedical (air rescue) or ground ambulances services. Conclusions for the training of emergency physicians are discussed.

PATIENTS AND METHODS

In a 3-year study period, a total of 9,274 pediatric emergencies covered by the ADAC air rescue service are compared to 4,344 pediatric patients of ground ambulance services in Saarland.

RESULTS

In aeromedical services pediatric emergencies are more frequent (12.9% vs. 6.4%), trauma predominates (59.9% vs. 35.6%) and severe injuries or diseases occur more frequently (30.5% vs. 15.0%). In both groups pediatric emergency cases are concentrated into very few diagnostic groups: more than one third of the cases involving pre-school children is due to convulsions. Respiratory diseases and intoxication are the next most frequent causes and are more common in ground ambulance patients. Head trauma is the most common diagnosis in cases of pediatric trauma, followed by musculoskeletal and thoracoabdominal trauma. All types of severe trauma are more frequent in pediatric patients of the aeromedical services.

CONCLUSIONS

Training of emergency physicians should include pediatric life support and specific information about frequent pediatric emergency situations. For emergency physicians in aeromedical services, an intensive training in pediatric trauma life support is also necessary.

Receptor activated C kinase is down-regulated in the male gonad of the marine bivalve mollusc Mya arenaria exposed to tributyltin (TBT)

This study was aimed at investigating the molecular mechanisms by which tributyltin (TBT) impairs the reproductive processes in the marine bivalve Mya arenaria. The suppression polymerase chain reaction subtractive hybridization (SSH) method was used to identify differentially expressed transcripts in the gonads of adult M. arenaria 72 h after a single injection of 160 ng TBT in the adductor muscle. Subtractive cDNA libraries comprising 322 clones were obtained. These clones were sequenced and corresponded to 55 female and 26 single male non-redundant cDNAs. Following similarity searches in genome databases, some of the transcripts could be assigned to cellular functions including mitochondrial respiration, structural proteins, structure of cytoskeleton, nucleic acid regulation, general metabolism and signal transduction. Among the potentially differentially regulated transcripts, Receptor for activated C kinase 1 (RACK1) represented 6% of the total down-regulated clones in males and the corresponding protein exhibited a high degree of similarity (80%) with the human polypeptide. The RACK1 cDNA from M. arenaria consists of 1085 bp, encoding a 318 deduced polypeptide which contains five internal tryptophan-aspartate (WD) repeats, six putative PKC phosphorylation sites, one tyrosine kinase site, four putative N-myristoylation sites as well as a transmembrane segment spanning amino acid 228-251. A significant down-regulation (by approximately 30% (p<0.05)) of RACK1 expression in male gonads exposed to TBT was confirmed by quantitative real-time RT-PCR. Transcript levels of RACK1 were higher in the female gonads than in the mantle, gills and male gonads. Gene expression as detected by in situ hybridization was strong in mature oocytes comparatively to primary germ cells. RACK1 may be a useful biomarker for TBT exposure in the reproductive system of bivalve molluscs.

High cancer cell death in syngeneic tumors developed in host mice deficient for the stromelysin-3 matrix metalloproteinase

Matrix metalloproteinases (MMPs) are extracellular enzymes. Some of them are known to be involved in tumor development and/or progression. Several cellular functions have been proposed for MMPs during malignant processes. Notably, they may be involved in tissue-remodeling processes through their ability to digest matrix components or to participate in tumor neoangiogenesis and, subsequently, in cancer cell proliferation. One of these MMPs, stromelysin-3 (ST3/MMP11), although devoid of enzymatic activity against the matrix components, is associated with human tumor progression and poor patient clinical outcome. Using several in vivo experimental models, it has been demonstrated that ST3 expression by the fibroblastic cells surrounding malignant epithelial cells promotes tumorigenesis in a paracrine manner. The present study was devoted to the identification of the cellular function underlying this ST3-induced tumor promotion using a syngeneic tumorigenesis model in mice. Our results show that ST3 exhibits a new and unexpected role for a MMP, because ST3-increased tumorigenesis does not result from increased neoangiogenesis or cancer cell proliferation but from decreased cancer cell death through apoptosis and necrosis. Thus, during malignancy, the cellular function of ST3 is to favor cancer cell survival in the stromal environment.

Identification and characterization of a novel gastric peptide hormone: the motilin-related peptide

BACKGROUND & AIMS

This study looked for new proteins with expression restricted to the gastric epithelium that may provide insight to the differentiation and function of the gastric unit.

METHODS

A novel complementary DNA was isolated and sequenced, and its expression was examined in mouse tissues at both messenger RNA and protein levels. Subcellular localization was studied using immunoelectron microscopy. The posttraductional processing of the protein was analyzed in vitro by protein microsequencing and in vivo by Western blotting.

RESULTS

We identified a novel protein that is mainly expressed by the secretory granules of the stomach enteroendocrine cells. This protein has sequence similarity with prepromotilin, the precursor of the motilin hormone and the motilin-associated peptide. As for the prepromotilin, a posttraductional maturation leads to a secreted peptide that is further cleaved at a dibasic site and gives rise to the motilin-related peptide (MTLRP) and MTLRP-associated peptide.

CONCLUSIONS

We have identified and characterized a novel gene encoding the preproMTLRP protein. MTLRP presents similarity to motilin and is specifically expressed by enteroendocrine cells of the stomach and therefore represents a novel hormone.

pS2/TFF1 interacts directly with the VWFC cysteine-rich domains of mucins

BACKGROUND & AIMS

Trefoil factors (TFFs) are secreted gastrointestinal proteins that have been shown to protect and promote healing of the gastrointestinal tract. Moreover, pS2/TFF1 is essential for normal differentiation of the gastric mucosa because deficient mice develop antropyloric adenomas. To date, it is unclear how TFFs mediate their functions.

METHODS

Using the yeast 2-hybrid system, we attempted to identify murine TFF1 interacting proteins by screening a stomach and duodenum complementary DNA (cDNA) expression library.

RESULTS

Four positive clones were isolated. Sequence and expression studies showed that they corresponded to the murine counterpart of human cDNA sequences encoding carboxy-terminal fragments of mMuc2 (489 residues) and mMuc5AC (427, 430, and 894 residues) mucin proteins. Mutagenesis experiments showed that TFF1 interacts with the 2 mucins through binding with their VWFC1 and VWFC2 (von Willebrand factor C) cysteine-rich domains.

CONCLUSIONS

These results show that the gastrointestinal protective effect of TFF1, and presumably of the other TFFs, is caused at least partially by their participation, via mucin binding, in the correct organization of the mucous layer that protects the apical side of the mucosa from deleterious luminal agents.

Expression of matrix metalloproteinases during murine chorioallantoic placenta maturation

A large body of experimental evidence supports the participation of two groups of extracellular proteases, matrix metalloproteinases (MMPs), and plasminogen activators/plasmin, in tissue remodeling in physiological and pathological invasion. In the late mouse placenta, several tissue remodeling and cell invasion processes take place. Spongiotrophoblast migration into maternal decidua, as well as decidual extracellular matrix remodeling require the coordinated action of extracellular proteolytic enzymes. Via Northern and in situ hybridization, we have analyzed the spatio-temporal expression patterns of members of the MMP family (stromelysin-3, gelatinases A and B), as well as their inhibitors TIMP-1, -2 and -3 in late murine placenta (days 10.5 to 18.5 of gestation). Gelatinase activity in placental extracts was assessed by substrate zymography. Gelatinase A and stromelysin-3 were found to be prominently expressed in decidual tissue; shortly after midpregnancy, the decidual expression patterns of gelatinase A and stromelysin-3 became overlapping with each other, as well as with the expression domain of TIMP-2. On the other hand, gelatinase B transcripts were expressed only by trophoblast giant cells at day 10.5, and were downregulated at later stages. TIMP-1 and TIMP-3 transcripts were detected in decidual periphery at day 10.5, while later the expression was restricted to the endometrial stroma and spongiotrophoblasts, respectively. The areas of stromelysin-3 expression were the same (giant trophoblasts) or adjacent (decidua) to those where urokinase (uPA) transcripts were detected, suggesting a possible cooperation between these proteinases in placental remodeling. We generated mice doubly deficient for stromelysin-3 and uPA, and report here that these mice are viable and fertile. Furthermore, these animals do not manifest obvious placental abnormalities, thereby suggesting the existence of compensatory/redundant mechanisms involving other proteolytic enzymes. Our findings document the participation of MMPs and their inhibitors in the process of late murine placenta maturation, and warrant the characterization of other members of the MMP family, like membrane type-MMPs, in this process.

[Extracellular proteases of stromal origin: contribution to tumor progression and therapeutic perspectives]

For a long time, extracellular proteinases were thought to be expressed by the cancerous cells and only able to cleave extracellular matrix components, in order to promote tumor cell invasion. Recent works have now demonstrated that these proteinases are currently synthesized by stromal fibroblastic cells and that some of them may exhibit additive function(s). These findings lead to a new therapeutical concept leading to target the activity of stromal proteinases, and most notably of the matrix metalloproteinases.

In vivo evidence that the stromelysin-3 metalloproteinase contributes in a paracrine manner to epithelial cell malignancy

Stromelysin-3 (ST3; Basset, P., J.P. Bellocq, C. Wolf, I. Stoll, P. Hutin, J.M. Limacher, O.L. Podhajcer, M.P. Chenard, M.C. Rio, P. Chambon. 1990. Nature. 348:699-704) is a matrix metalloproteinase (MMP) expressed in mesenchymal cells located close to epithelial cells, during physiological and pathological tissue remodeling processes. In human carcinomas, high ST3 levels are associated with a poor clinical outcome, suggesting that ST3 plays a role during malignant processes. In this study we report the ST3 gene inactivation by homologous recombination. Although ST3 null mice (ST3-/-) were fertile and did not exhibit obvious alterations in appearance and behavior, the lack of ST3 altered malignant processes. Thus, the suppression of ST3 results in a decreased 7, 12-dimethylbenzanthracene-induced tumorigenesis in ST3-/- mice. Moreover, ST3-/- fibroblasts have lost the capacity to promote implantation of MCF7 human malignant epithelial cells in nude mice (P < 0.008). Finally, we show that this ST3 paracrine function requires extracellular matrix (ECM)-associated growth factors. Altogether, these findings give evidence that ST3 promotes, in a paracrine manner, homing of malignant epithelial cells, a key process for both primary tumors and metastases. Therefore, ST3 represents an appropriate target for specific MMP inhibitor(s) in future therapeutical approaches directed against the stromal compartment of human carcinomas.

Tumor necrosis factor receptor associated factor 4 (TRAF4) expression pattern during mouse development

This is the first in situ hybridization analysis of expression of a tumor necrosis factor (TNF) receptor associated factor (TRAF) during development. TRAF4 is observed throughout mouse embryogenesis, most notably during ontogenesis of the central (CNS) and peripheral (PNS) nervous system, and of nervous tissues of sensory organs. TRAF4 is preferentially expressed by post-mitotic undifferentiated neurons. Interestingly, TRAF4 remains expressed in the adult hippocampus and olfactory bulb, known to contain multipotential cells responsible for neoneurogenesis.

Chromosomal assignment and expression pattern of the murine Lasp-1 gene

The human Lasp-1 (LIM and SH3 protein) gene was previously identified by differential screening of a breast cancer-derived metastatic lymph node cDNA library. It was located on the q12-q21 region of human chromosome 17 and was shown to be amplified and overexpressed in 12% of breast tumors. Lasp-1 defines a new LIM-protein subfamily, as it associates a C-terminal Src homology 3 (SH3) domain to a N-terminal LIM motif. In this study, the isolation and characterization of the cDNA encoding the mouse Lasp-1 protein are described, and it is shown to be highly conserved with its human counterpart. In addition to the LIM and SH3 domains, both human and mouse Lasp-1 contain an actin-binding domain. The mouse gene was mapped by in situ hybridization to the 11C-11D region of chromosome 11. Northern blot analysis shows that this gene is expressed from 7.5 to 17.5 days post-coitum of mouse embryogenesis and in almost all adult tissues.

Spontaneous iron overload in Sprague-Dawley rats

In a review of the toxicological studies performed in our laboratory during the period 1986-1995, we occasionally observed significant iron overloading in the liver. Liver tissue was examined by light and electron microscopy, and the results were analyzed by sex and age (7, 9, 11, 19, 31, 59, and 111 wk). The intensity of iron overload increased with age: the accumulation began in pericanalicular siderosomes of periportal hepatocytes and extended progressively to the entire lobule and also to nonhepatocytic cells (Kupffer cells in sinusoids and macrophages around bile ducts in portal tracts) and occasionally with distortion of sinusoids by sideroblastic nodules and moderate enlargement of portal tracts in the oldest animals. No significant inflammatory infiltrates, degeneration, necrosis or fibrosis were noted. Hepatocyte pigmentation alone was prominent at 9 and 11 wk. The frequency of pigmentation of parenchymal and nonhepatocytic cells increased from 9 wk for females; in males, this was seen only at 111 wk. The intensity of pigmentation of nonhepatocytic cells versus parenchymal cells increased with aging. The frequency of those different types of iron overloading was higher for females up to 111 wk. The pathology of spontaneous iron overloading in the Sprague-Dawley rat, described here in spite of differences, has some similarities to that of human hereditary hemochromatosis.

Gastric mucosa abnormalities and tumorigenesis in mice lacking the pS2 trefoil protein

To determine the function of the pS2 trefoil protein, which is normally expressed in the gastric mucosa, the mouse pS2 (mpS2) gene was inactivated. The antral and pyloric gastric mucosa of mpS2-null mice was dysfunctional and exhibited severe hyperplasia and dysplasia. All homozygous mutant mice developed antropyloric adenoma, and 30 percent developed multifocal intraepithelial or intramucosal carcinomas. The small intestine was characterized by enlarged villi and an abnormal infiltrate of lymphoid cells. These results indicate that mpS2 is essential for normal differentiation of the antral and pyloric gastric mucosa and may function as a gastric-specific tumor suppressor gene.

Stromelysin-3 in the biology of the normal and neoplastic mammary gland

Stromelysin-3 (ST3) is an extracellular proteinase predominantly expressed in fibroblasts. The particular structural features and in vitro functions of this molecule suggest it could be the first member of a new subgroup of the matrix metalloproteinase family. ST3 is transiently expressed during mammary gland post-weaning involution, embryonic implantation, various organogeneses, and during amphibian metamorphosis. Moreover, ST3 is expressed in a panel of human invasive carcinomas including breast, colon, and head and neck carcinomas. Almost all ST3-expressing tissues show intense extracellular matrix remodeling activities including the loss of basement membrane integrity. Thus, either directly, or indirectly in association with other proteinases, ST3 might be involved in tissue remodeling processes occurring in both physiological and pathological processes. In vitro and in vivo studies using malignant cells stably transfected in such a way as to modulate their ST3 expression levels indicate that ST3 modifies neither cell proliferation nor invasive properties, but rather favors tumor cell survival in host tissues. This hypothesis is consistent with clinical data showing that ST3 expression could be predictive of tumor progression leading to metastases.

Embolization of a dural arteriovenous fistula of the ventral cervical spinal canal in a nine-year-old boy

A 9-year-old patient presented with an acute left hemiparesis secondary to an intradural hemorrhage of the cervical spinal cord. Angiography revealed a dural arteriovenous (AV) fistula with multiple venous aneurysms fed by a radicular branch of the right vertebral artery. This AV fistula did not contribute blood flow to the cervical segment of the spinal cord, which was tested by an intra-arterial injection of methohexital. Interruption of the fistula was possible by transluminal embolization with polyvinyl alcohol and silk. At a 6-month follow-up, the patient was neurologically intact, and angiography demonstrated no AV fistula. This case illustrates an unusual presentation of a dural AV fistula. Dural AV fistulas are rare in the cervical region and extremely unusual in patients less than 20 years of age. The lesion proved to be amenable to transluminal embolization alone, without the need for surgery, with a dramatic resolution of the neurological deficit.

[Use of local cobalt therapy in peripheral neuropathies associated with chronic lymphopathies (lymphoses). 2 cases with histo-immunologic and ultrastructural records]

In two cases of peripheral neuropathy, associated with a chronic lymphopathy, cobalt therapy to the lower limbs provided considerable relief of pain, with partial motor recovery. The disappearance after cobalt therapy of the lymphoid infiltrate of the peripheral nerve leads to discussion of the pathogeni role of this infiltrate. Immunofluorescent and electron microscopic studies form the basis of a discussion of the mechanism of involvement of the peripheral nerve non-secreting lymphopathies (chronic lymphoid leukaemia) and in secreting lymphopathies (Waldenström's disease).

[Encephalic pseudotumoral toxoplasmosis in the course of blood diseases]

The authors report two cases, the first pathological and the second clinical of pseudo-tumoural cerebral toxoplasmosis, occurring during the course of blood diseases. They refer to the conditions of appearance of this rare complication, with only twenty cases recorded in the literature, during malignant blood diseases. They stress the primordial role of immunological deficiency related either to the underlying disease (especially Hodgkin's disease) or to immuno-suppressive therapy. The clinical picture, with little in the way of typical features, is thus that of a diffuse méningo-encéphalitis. Pseudo-tumoural forms are rare. The authors also stress the minimum conditions required for the validity of the dye test and the value of the diagnosis of cerebral toxoplasmosis. An association of sulphadiazine-purimethamine, active and effective, cured the second patient.

Pulmonary function: relation to aging, cigarette habit, and mortality

The relation of pulmonary function to aging and cigarette habits has been examined cross sectionally and longitudinally in the Framingham cohort. On cross-sectional analysis, women were found to have lower forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV-1) values than men even after adjusting for height. Their FEV-1 percent was, on the other hand, higher than those of men. As the population aged over 10 years, their FVC and FEV-1 declined 9% to 27% depending upon age and sex. The FEV-1 percent, however, showed a decline only in the older age groups. In a cross-sectional analysis, cigarette smoking showed an inverse association to FVC and FEV-1 percent. Longitudinally, cigarette smokers showed a more rapid decline in FVC in 10 years than nonsmokers. On giving up smoking their FVC became more like that of the nonsmokers. A striking relation of FVC to mortality was noted in both sexes, which is not accounted for by associated cigarette habits.

[Study of neurological manifestations of chronic lymphatic leukemia (lymphosis). Role of associated globulin anomalies (apropos of 8 cases)]

The authors emphasize the relative frequency of neurological symptoms in lymphatic leukaemia. Clinically, these cause more or less diffuse encephalitic or multineuritic syndromes, generally a combination of the two. Their pathogenesis is usually connected with lymphoid tissue infiltration into either the meninges or the vascular sheaths of the central nervous system or the sheaths of the roots or of the peripheral nerves. The authors stress the possible function of immunoglobulin abnormalities of the C.S.F. indicative of the presence of the leukaemic process within the nervous system. This pathogenesis prompts the use of therapeutic methods directly attacking leukaemic infiltration of the nervous system (focal cobalt therapy, intrathecal chemotherapy) and the authors have found that these give favourable results.