Major outputs of the neocortex are conveyed by corticothalamic axons (CTA), which form reciprocal connections with thalamocortical axons, and corticosubcerebral axons (CSA) headed to more caudal parts of the nervous system. Previous findings establish that transcriptional programs define cortical neurons identity and suggest that CTA and thalamic axons may guide each other, but the mechanisms governing CTA versus CSA pathfinding remain elusive. Here, we show that thalamocortical axons are required to guide pioneer CTA away from a default CSA-like trajectory. This process relies on a hold in the progression of cortical axons, or waiting period, during which thalamic projections navigate towards cortical axons. At the molecular level, Sema3E/PlexinD1 signaling in pioneer cortical neurons mediates a “waiting signal” required to orchestrate the mandatory meeting with reciprocal thalamic axons. Our study reveals that temporal control of axonal progression contributes to spatial pathfinding of cortical projections and opens novel perspectives on brain wiring.
corticothalamic; thalamocortical; axon guidance; reciprocal connections; waiting period; Sema3E; PlexinD1; handshake
Resonant elastic x-ray scattering (REXS) is an exquisite element-sensitive tool for the study of subtle charge, orbital, and spin superlattice orders driven by the valence electrons, which therefore escape detection in conventional x-ray diffraction (XRD). Although the power of REXS has been demonstrated by numerous studies of complex oxides performed in the soft x-ray regime, the cross section and photon wavelength of the material-specific elemental absorption edges ultimately set the limit to the smallest superlattice amplitude and periodicity one can probe. Here we show – with simulations and REXS on Mn-substituted Sr3Ru2O7 – that these limitations can be overcome by performing resonant scattering experiments at the absorption edge of a suitably-chosen, dilute impurity. This establishes that – in analogy with impurity-based methods used in electron-spin-resonance, nuclear-magnetic resonance, and Mössbauer spectroscopy – randomly distributed impurities can serve as a non-invasive, but now momentum-dependent probe, greatly extending the applicability of resonant x-ray scattering techniques.
This article outlines the role of 16α-[18F]fluoro-17β-oestradiol (18F-FES) positron emission tomography (PET) combined with 2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG) in patients with oestrogen-related tumours for evaluating tumour phenotype. 18F-FES-PET combined with 18F-FDG is helpful in characterising the distinct phenotypic features of oestrogen-related tumours; that is, inter- and intrapatient tumour heterogeneity, which indicates its great potential as a determinant of individualised treatment and a prognostic predictor for patients with oestrogen-related tumours.
The precise time of stroke onset during sleep is difficult to specify, but this has a considerable influence on circadian variations of stroke onset.
To investigate circadian variations in situations at stroke onset—that is, in the waking state or during sleep—and their differences among subtypes.
12 957 cases of first‐ever stroke onset diagnosed from the Iwate Stroke Registry between 1991 and 1996 by computed tomography or magnetic resonance imaging were analysed. Circadian variations were compared using onset number in 2‐h periods with relative risk for the expected number of the average of 12 2‐h intervals in the waking state or during sleep in cerebral infarction (CIF), intracerebral haemorrhage (ICH) and subarachnoid haemorrhage (SAH).
ICH and SAH showed bimodal circadian variations and CIF had a single peak in all situations at onset, whereas all three subtypes showed bimodal circadian variations of stroke onset in the waking state only. These variations were different in that CIF showed a bimodal pattern with a higher peak in the morning and a lower peak in the afternoon, whereas ICH and SAH had the same bimodal pattern with lower and higher peaks in the morning and afternoon, respectively.
Sleep or status in sleep tends to promote ischaemic stroke and suppress haemorrhagic stroke. Some triggers or factors that promote ischaemic stroke and prevent haemorrhagic stroke in the morning cause different variations in the waking state between ischaemic and haemorrhagic stroke.
In vertebrates, the taste system provides information used in the regulation of food ingestion. In mammals, each cell group within the taste buds expresses either the T1R or the T2R taste receptor for preference–aversion discrimination. However, no such information is available regarding fish. We developed a novel system for quantitatively assaying taste preference–aversion in medaka fish. In this study, we prepared fluorescently labeled foods with fine cavities designed to retain tastants until they were bitten by the fish. The subjects were fed food containing a mixture of amino acids and inosine monophosphate (AN food), denatonium benzoate (DN food) or no tastant (NT food), and the amounts of ingested food were measured by fluorescence microscopy. Statistical analysis of the fluorescence intensities yielded quantitative measurements of AN food preference and DN food aversion. We then generated a transgenic fish expressing dominant-negative Gαi2 both in T1R-expressing and in T2R-expressing cells. The feeding assay revealed that the transgenic fish was unable to show a preference for AN food and an aversion to DN food. The assay system was useful for evaluating taste-blind behaviors, and the results indicate that the two taste signaling pathways conveying preferable and aversive taste information are conserved in fish as well as in mammals.
Feeding behavior; G-protein; phospholipase C-beta 2; signal transduction; taste receptor; transgenic fish
Aims: To evaluate a new delivery system of 5-fluorouracil (5-FU) using 5-fluorocytosine (5-FC) as a prodrug and cytosine deaminase induced in vitro and in vivo.
Methods: Fibroblastic cells from rabbit Tenon's capsule were cultured. The cells were exposed to 5-FU and 5-FC with or without cytosine deaminase induced by recombinant adenovirus. In the in vitro study, cell proliferation and DNA synthesis were assessed by MTS, BrdU assay. The effect of 5-FC removal after the treatment of 5-FC and cytosine deaminase induction was also assayed. In the in vivo study cells with or without cytosine deaminase induction were transplanted into the subconjunctival space of mice, followed by eye drops of 1000 μg/ml of 5-FC three times a day. The mice were sacrificed at days 1, 5, and 10, then the cells transplanted were evaluated.
Results: Cell proliferation was inhibited by exposure to 5-FU in a dose dependent manner; however, up to 1000 μg/ml of 5-FC did not affect cell proliferation. Cell proliferation was inhibited by exposure to 5-FC in a time dependent manner with induction of cytosine deaminase following infection of recombinant adenovirus. When 5-FC was removed 3 or 6 days after the treatment, the cells grew again. The effect was reproduced in the in vivo model of subconjunctival cellular proliferation although 5-FC was administrated as eye drops. There were no cases with corneal erosion.
Conclusion: Cell proliferation was inhibited by co-exposure of 5-FC and cytosine deaminase. This new delivery system may merit controlled delivery of 5-FU after filtering surgery.
5-fluorouracil; 5-fluorocytosine; cytosine deaminase; adenoviral vector; gene therapy; filtering surgery
Cerebral arteriovenous malformations (CAVM) can be associated with Hereditary Haemorrhagic Telangiectasia (HHT), a dominantly inherited vascular disorder with variable penetrance and expressivity. The presentation and angiographic features were analysed retrospectively. The purpose is to point to special groups of AVM patients within the overall CAVMs and to discuss the issue of screening.
We reviewed 34 cases of HHT-related CAVM from the data bank in Bicêtre from 1985-2003. In Spinal cord AVM (SCAVM) there were 194 patients with 5 HHT. HHT was diagnosed when at least two criteria were met; cutaneous telangiectasia, epistaxis, visceral AVMs, angiographic findings of AVF and first degree family history.
Intracranial haemorrhage was the presenting symptom in 8.8% and the risk of haemorrhage in the natural history was 0.7% per year. The commonest angiographic features in adults are nidus(81.8%) and multiplicity(45.5%), while in the paediatric group venous ectasia and giant pouches(91.3%), AVF(69.6%) and multiplicity(52.2%). In spinal cord lesions macrofistulas are demonstrated in 83% of HHT with no multiplicity.
HHT-related CAVMs present as multiple lesions, cortical in location, micro AVMs or AVF. HHT in SCAVM is expressed as single macro AVF, especially in the paediatric group. AVF in children are highly suggestive of HHT. We do not recommend screening in HHT adult patients for CAVM, while in the paediatric population, screening could be recommended at six months of age for cerebrospinal localization. These patients should be screened for Pulmonary AVF, which needs to be treated in priority.
hereditary haemorrhagic telangiectasia (HHT), Rendu-Osler Weber (ROW), cerebral arteriovenous malformations (CAVM), spinal cord arteriovenous malformations (SCAVM), children, intracranial haemorrhage (ICH)
Background and Purpose
Dural Arteriovenous Shunt (DAVS) in children include Dural sinus malformation (DSM), infantile and adult types. They are rare and seldom reported. Our purpose was to highlight the angiographic features of the DSM sub group for prognosis of clinical evolution and outcome and to lay guidelines for management.
Methods: From a dedicated neurovascular data bank, there were 52 cases of arteriovenous dural shunts in children from 1985 to 2003. Of these, there were 30 patients with DSM, which we analysed the various angioarchitecture, presentation and neurological outcome. Children clinical status was evaluated and scored at admission and follow up.
There was an overall male dominance of 2:1. Antenatal diagnosis was obtained in 8/30 (26.7%) cases. Mean age of diagnosis was 5 months. Mean age at first consultation was 8.7 months. No patient was diagnosed during childhood. The most common clinical presentations were macrocrania 76.7%, seizures 23.3% and mental retardation 23.3%. In 14/30 (35.7%) of the patients, the therapeutic decision was to manage conservatively; in 5/14 (30.7%) with predictable favourable evolution and in 9/14 (64.3%) with irreversible poor neurological outcome. In the remaining 16/30 (53.3%) patients, endovascular treatment was performed. In 12/16 (75.0%) patients the neurological outcome was good, 3/16 (18.8%) patients had unfavourable evolution despite embolization. There was no morbidity mortality related to the procedures themselves. 1/16 (6.3%) patient was lost to follow-up. Overall 12/29 (45.8%) patients had an unfavourable neurological outcome with 11 patients dead and 1 with severe neurological deficit. In the surviving group of children, 17/18 (94.4%) have a good neurological outcome; in 10/18 (55.5%) the lesion is morphologically excluded.
DSM is rare disease with high mortality. They usually proceed to either total or partial spontaneous thrombosis before the age of 2 thus compromising normal cerebral venous drainage. DSM away from the torcular, good cavernous sinus, cavernous capture of sylvian veins, absence of pial veins, straight sinus or superior sagital sinus (SSS) reflux and absence of jugular bulb dysmaturation represent factors of good prognosis. Such patients will highly benefit for endovascular treatment. In partial endovascular approach the aim being is to separate the brain drainage from DSM drainage. This will be achieved by the transarterial approach to the associated mural arterio-venous shunts (AVS) and by disconnecting the pial reflux by transvenous route.
dural sinus malformation, dural arteriovenous shunt, neonates, children, malformations, embolization, antenatal diagnosis, intracerebral haemorrhage
BACKGROUND—It was recently reported that A to G transition mutations at positions 2143 and 2144 in the 23S rRNA gene are associated with clarithromycin resistance in Helicobacter pylori.
AIMS—To study the incidence and mechanism of development of clarithromycin resistance by analysing these mutations.
SUBJECTS—Eighty two H pylori positive patients who had an endoscopic examination and no history of treatment with macrolide antibiotics.
METHODS—Clarithromycin resistance was screened for by polymerase chain reaction-restriction fragment length polymorphism of the 23S rRNA gene coupled with antibiotic susceptibility testing. In clinical isolates with mutations or resistance, mutations in individual colonies were analysed by direct sequencing.
RESULTS—Of the 79 amplicons (DNA fragments amplified by polymerase chain reaction), Alw26I and MboII digestion disclosed the mutation in four (5%) and one (1%) respectively. However, the Alw26I cleavage was incomplete in two of the four amplicons, as was the MboII cleavage. Individual colony analysis of the isolates with incomplete cleavage patterns showed the presence of both wild type and mutated strains in the 23S rRNA genes.
CONCLUSIONS—Both clarithromycin sensitive and resistant strains colonised in some patients with no history of exposure to macrolides. The results suggest that resistant strains may not be formed but selected by clarithromycin administration.
Keywords: Helicobacter pylori; clarithromycin resistance; 23S rRNA gene; point mutation; mixed strain colonisation
AIMS: To clarify the relation between the serum titre of anti-Helicobacter pylori (H pylori) antibody and the extent of intestinal metaplasia of the gastric mucosa. METHODS: The serum anti-H pylori IgG titres of 95 asymptomatic individuals (mean age 65 years) undergoing an annual health examination were measured and compared with the extent of intestinal metaplasia (absent, moderate, or extensive), determined by examination of multiple endoscopic mucosal biopsy specimens. Serum pepsinogen I (PGI) levels, as a marker for gastric atrophy, were also measured. RESULTS: The prevalence of seropositivity for H pylori antibody was high (> 80%), regardless of the extent of metaplasia. However, there was a negative association between the extent of metaplasia and the anti-H pylori titre: 75% of the subjects in the group without metaplasia had high (3+) antibody levels, as did 43% with moderate, and 37% with extensive metaplasia (absent v extensive). The inverse relation between the titre and the extent of metaplasia was evident when examined in those with normal PGI (> 30 ng/ml), whereas no such relation was apparent in subjects with low PGI (< or = 30 ng/ml). CONCLUSIONS: The anti-H pylori titre correlates inversely with the extent of intestinal metaplasia, particularly in subjects with less marked gastric atrophy.
Lymphangioma of the oesophagus is exceedingly rare. Seven cases (including our present case) have been reported in the world and are reviewed.
UV damage-specific binding proteins are considered to play important roles in early responses of cells irradiated with UV, including damage recognition in the DNA repair process. We have surveyed nuclear and cytoplasmic proteins which bind selectively to UV-irradiated DNA using an electrophoretic mobility shift assay. We detected four distinct binding activities with different mobilities in fractions separated from HeLa cells by heparin chromatography. Three of them were found in nuclear extracts and one in cytoplasmic extracts. We purified one of the binding factors from nuclear extracts to homogeneity, which was designated NF-10 (the 10th fraction of nuclear extract on heparin chromatography). It migrated as a 40 kDa polypeptide in SDS-PAGE, and bound to UV-irradiated double- stranded DNA but not to unirradiated DNA. The binding pattern of the NF-10 protein to DNA irradiated with UV corresponded to the induction kinetics of (6-4) photoproduct. Removal of (6-4) photoproducts from UV- irradiated DNA by (6-4) photoproduct-specific photolyase diminished the binding of NF-10 protein. These results suggest that the NF-10 protein binds to UV-damaged DNA through (6-4) photoproduct. Immunoblot analysis using a monoclonal antibody revealed that the NF-10 protein was expressed in cell lines from all complementation groups of xeroderma pigmentosum, indicating that the NF-10 protein is a novel UV-damaged-DNA binding protein.
The aetiology of Crohn's disease remains unknown, although evidence for a viral cause has long been sought. Recent studies have shown inflammation of the submucosal microvascular endothelium and granulomata, and endothelial cell cytoplasmic inclusions, consistent with paramyxovirus, were identified by electron microscopy suggesting a persistent measles virus infection in Crohn's disease. Measles, mumps, and rubella viruses were tested for Crohn's disease by polymerase chain reaction (PCR). RNA was extracted from resected intestinal specimens from 15 patients with Crohn's disease, 14 with ulcerative colitis, and 14 controls without inflammatory bowel disease. This was used to perform nested PCR after reverse transcription (RT) of the RNA to cDNA with primer pairs directed against two regions in the genome of the measles virus and one region in the mumps and rubella viral genomes. Despite enhanced sensitivity of nested RT-PCR, measles, mumps, and rubella viral genomic sequences were not found in any intestinal specimen.
The gene encoding the 17,000-molecular-weight genus-common antigen (17K genus-common antigen) has been cloned and sequenced from Rickettsia japonica. The primer pair used for PCR was designed from this sequence. A 357-bp fragment was observed by amplifying the genomic DNA from R. japonica and also the DNA from blood clots of patients with spotted fever group rickettsiosis. The results indicated that this method is suitable for the diagnosis of spotted fever group rickettsiosis in Japan.
Recombinant viruses between the virulent Mahoney and attenuated Sabin 1 strains of poliovirus type 1 were subjected to neurovirulence tests using a transgenic (Tg) mouse line, ICR-PVRTg1, that carried the human poliovirus receptor gene. The Tg mice were inoculated intracerebrally with these recombinant viruses and observed for clinical signs, histopathological lesions, and viral antigens as parameters of neurovirulence of the viruses. These parameters observed in the Tg mice were different for different inoculated viruses. Dose-dependent incidences of paralysis and of death were observed in the Tg mice inoculated with any viruses used. This indicates that values of 50% lethal dose are useful to score a wide range of neurovirulence of poliovirus. The neurovirulence of individual viruses estimated by the Tg mouse model had a strong correlation with those estimated by monkey model. Consequently, the mouse tests identified the neurovirulence determinants on the genome of poliovirus that had been identified by monkey tests. In addition, the mouse tests revealed new neurovirulence determinants, that is, different nucleotides between the two strains at positions 189 and 21 and/or 935 in the 5'-proximal 1,122 nucleotides. The Tg mice used in this study may be suitable for replacing monkeys for investigating poliovirus neurovirulence.
Nuclear deoxyribonucleic acid (DNA) content of hepatocellular carcinoma (HCC) in 41 South African and 47 Japanese patients at autopsy was analysed by dual-wavelength microspectrophotometry. The DNA distribution patterns were classified as type I, II, III or IV and as low ploidy (types I, II) or high ploidy (types III, IV), according to the degree of dispersion. We found a significantly higher incidence of high ploidy in South African HCC than in Japanese HCC. Moreover, type IV was significantly more frequent among South Africans than among the Japanese. These findings demonstrate that large differences in biological characteristics and clinical behaviour of HCC between South Africa and Japan may reflect differences in DNA distribution patterns which we observed between these two races.