FLAIR Vascular Hyperintensities as a Surrogate of Collaterals in Acute Stroke: DWI Matters

BACKGROUND AND PURPOSE

FLAIR vascular hyperintensities are thought to represent leptomeningeal collaterals in acute ischemic stroke. However, whether all-FLAIR vascular hyperintensities or FLAIR vascular hyperintensities-DWI mismatch, ie, FLAIR vascular hyperintensities beyond the DWI lesion, best reflects collaterals remains debated. We aimed to compare the value of FLAIR vascular hyperintensities-DWI mismatch versus all-FLAIR vascular hyperintensities for collateral assessment using PWI-derived collateral flow maps as a reference.

MATERIALS AND METHODS

We retrospectively reviewed the registries of 6 large stroke centers and included all patients with acute stroke with anterior circulation large-vessel occlusion who underwent MR imaging with PWI before thrombectomy. Collateral status was graded from 1 to 4 on PWI-derived collateral flow maps and dichotomized into good (grades 3-4) and poor (grades 1-2). The extent of all-FLAIR vascular hyperintensities and FLAIR vascular hyperintensities-DWI mismatch was assessed on the 7 cortical ASPECTS regions, ranging from 0 (absence) to 7 (extensive), and associations with good collaterals were compared using receiver operating characteristic curves.

RESULTS

Of the 209 included patients, 133 (64%) and 76 (36%) had good and poor collaterals, respectively. All-FLAIR vascular hyperintensity extent was similar between collateral groups (P = .76). Conversely, FLAIR vascular hyperintensities-DWI mismatch extent was significantly higher in patients with good compared with poor collaterals (P < .001). The area under the curve was 0.80 (95% CI, 0.74-0.87) for FLAIR vascular hyperintensities-DWI mismatch and 0.52 (95% CI, 0.44-0.60) for all-FLAIR vascular hyperintensities (P < .001 for the comparison), to predict good collaterals. Variables independently associated with good collaterals were smaller DWI lesion volume (P < .001) and larger FLAIR vascular hyperintensities-DWI mismatch (P = .02).

CONCLUSIONS

In acute ischemic stroke with large-vessel occlusion, the extent of FLAIR vascular hyperintensities does not reliably reflect collateral status unless one accounts for DWI.

[Respiratory distress syndrome, early postnatal corticoid therapy and periventricular leukomalacia]

The aetiology of cavitating periventricular leukomalacia (cPVL) involves pre and perinatal factors. Early postnatal dexamethasone has been associated with an increase in cerebral palsy but its role in the development of PVL remains uncertain.

OBJECTIVES

(1) Reevaluate major factors associated with cPVL, (2) Evaluate the potential effect of early postnatal dexamethasone.

METHOD

This retrospective case-control study (matched for gestational age, birth weight, twin pregnancy and date of birth) compared 50 premature infants with cPVL diagnosed between D7 and D45 from 1995 to 2000 and 50 matched control newborns with normal serial neurosonograms. A data base with 97 selected perinatal variables was used to perform logistic regression analysis in controlling confounding variables, the results are expressed as adjusted Odds Ratio (OR) with 95% confidence interval.

RESULTS

The two populations were comparable for gestational age (median: 29.3 weeks, range: 24.4-34.7) and birth-weight (1297 g, 645-2130 g). The annual incidence of cPVL in preterm infants with a gestational age < 33 weeks varied from 1995 to 2000: 1.3%, 4.5%, 13.4%, 2.1%, 3%, 2.9%. Early postnatal dexamethasone was used in 23 of the newborns who developed cPVL (between november 1996 and march 1998). The only antenatal factor associated with cPVL was cardiac decelerations (28% vs 14%, OR = 3.4, 1.1-11.3). The postnatal risk factors were respiratory distress syndrome requiring the use of rescue surfactant (78% vs 38%, OR = 4.2, 1.4-11.9) and early postnatal dexamethasone at the time it was used (78% vs 17%, OR = 17.1, 3.9-73).

CONCLUSION

The use of rescue surfactant and of early postnatal dexamethasone in preterm infants with respiratory distress syndrome were independently associated with the subsequent occurrence of cPVL. Cardiac deceleration was the only antenatal factor associated with cPVL.

Topology inversion of CYP2D6 in the endoplasmic reticulum is not required for plasma membrane transport

The presence of CYP2D6 at the surface of isolated rat and human hepatocytes and its recognition by autoantibodies were reported recently. We wondered whether the unexpected outside orientation at the plasma membrane could be related to topological inversion (luminal-oriented form) of cytochrome P450 in the endoplasmic reticulum. To examine the potential role of cDNA polymorphism, a CYP2D6 variant carrying three positive charges at the amino terminus (2D6ext) was constructed and expressed in yeast. Immunoblotting, flow cytometry, and electron microscopy showed that wild-type CYP2D6 expressed in yeast was present on the outer face of the cell plasma membrane in addition to the regular microsomal location. This location reproduces the hepatocyte situation. 2D6ext expressed in yeast and COS7 cells seemed to be partially N-glycosylated and was located at the plasma membrane surface. Nevertheless, the glycosylated form was not enriched in the plasma membranes compared with microsomes. The relationship between CYP2D6 and 2D6ext topologies and catalytic competence was tested. Cumene hydroperoxide-dependent dextromethorphan demethylation was performed on microsomal vesicles after combined proteolysis and immunoinhibition experiments. CYP2D6 activity was completely abolished, whereas the glycosylated and luminal-oriented fraction of 2D6ext remained active. This suggests that a luminal-oriented glycosylated form is not involved in cytochrome P450 transport to the plasma membrane. Yeast thus reproduces the unusual CYP2D6 plasma membrane location and orientation, which do not require sequence alteration, glycosylation, or even an inverted endoluminal orientation.

[Deep morphea-type lesions, first manifestations of lymphocytic lymphoma]

INTRODUCTION

The association between scleroderma and lymphoma is uncommon and can sometimes query an fortuitous association. More particular are observations where chronological and histological features show an evident link between a tumorous process and sclerosis.

OBSERVATION

This case concerns a man 69 years old who was treated for one year for partial subcutaneous sclerosis present on his legs, thighs, fore-arms, and on the upper part of the trunk. No signs were present of visceral involvement evoking a systemic scleroderma and histology showed an intrication of a deep sclerosis, fasciitis and a tumoral lymphoma process. Diagnosis of lymphocytic lymphoma was confirmed. Initiating a chemotherapy (CHOP) allowed for a reduction of the sclerosis which didn't respond to the only corticotherapy.

DISCUSSION

This observation can be linked to the association of fasciitis and lymphoma identified by Naschitz et al, but is different by: 1) the clinical aspect which correspond more to deep morphea lesions; 2) the histological link between sclerosis and lymphoma. This last point suggest that it is the tumoral population which have induced the sclerosis process linked to the secretion of pro-inflammatory factors. In adverse cases with longer delay between lymphoma and scleroderma this association may be fortuitous.

Dental injuries among schoolchildren aged from 6 to 15, in Rennes (France)

A representative sample of 2020 schoolchildren, aged 6 to 15 years, was randomly selected from 85 state and private schools in Rennes and distributed in 10 groups, according to their age. Type and prevalence of dental injuries were determined in each group, using Ellis & Davey's classification, giving rise to a subset of 345 subjects. Simple enamel fracture was the predominant injury (59.4%), occurring most often on maxillary central incisors. Most time (77.1%), the trauma affected only one tooth. Mean prevalence of dental injuries was 13.6% from 2020 subjects. Boys showed a higher prevalence than girls (respectively 17% and 10.2%), but this difference was only significant for age-groups 12 and 13 (p < 0.001) and for the whole group of 6-15 (p < 0.001).

[Oral and dental health status in a population of schoolchildren aged 5 to 15 years in Wallis]

This study was performed in 1992 with three aims: to assess precisely the prevalence of dental carries in the child population of Wallis Island; to evaluate the need for dental care; and create a database allowing the oro-dental status to be followed and the effectiveness of preventive programmes to be assessed. The total population of the Wallis Islands according to the 1990 (the most recent) census was 8,973 living in twenty villages. The population was classified into four ethnic groups: Wallisian (94.4%), Futunian (1.2%), European (3.9%) and miscellaneous (0.5%). The lifestyle of the population is traditional and there is virtually no manufacturing, overseas trade or tourism. The population of Wallis Island is young, with 56.6% of the population under 20 years old. Almost all the children attended school from the age of 6 to the age of 19 [3]. Half the Island's children (n = 1407) between the ages of 5 and 15 years old were classified into 11 age groups and were examined. Children from all schools were included in the study group which was representative of the child population of Wallis Island (94.4% were Wallisian) (table 1). The study was performed according to the 1988 WHO guidelines [4] and Cahen [5]. At age 5, a mean of 3.26 teeth had erupted. The permanent dental set (other than the 3rd molars) were present by age 12 years in virtually all cases. The percentage that had carrie-free permanent teeth were 89.9% at age 5, 59.9% at age 6, 22% at age 12 and only 13.4% at age 15.(ABSTRACT TRUNCATED AT 250 WORDS)

Calmodulin is essential for assembling links necessary for exocytotic membrane fusion in Paramecium

Calmodulin has long been suspected to be involved in calcium-regulated exocytosis but its precise site(s) of action has not yet been identified. In Paramecium, a genetic approach to the problem is possible as in vivo-selected mutations in the calmodulin gene that prevent the activation of some channels have been characterized. Three of these calmodulin mutants were examined for exocytotic capacity and the mutant cam1 was found to be defective for exocytosis at 35 degrees C. The loss of exocytotic capacity in cam1 cells can be restored by transformation with the wild-type calmodulin gene, demonstrating that its exocytotic lesion is indeed due to the mutation in the calmodulin gene. The cam1 mutant displays abnormal exocytotic sites at the non-permissive temperature: it lacks the links ('rosettes' of intramembranous particles in the plasma membrane and the fibrous 'connecting material') which normally connect plasma and trichocyst membranes. Upon shift of cam1 cells from the permissive to a non-permissive temperature, performed sites remain functional. These results demonstrate that calmodulin is necessary for the assembly of these links at the exocytotic site. These results do not, however, exclude the possibility of calmodulin also being involved in Ca(2+)-dependent steps of the stimulus-exocytosis coupling.

[Idiopathic eruptive macular pigmentation]

BACKGROUND

Hyperpigmentation can be due to different cause or have no apparent cause.

CASE REPORT

A 4 year-old boy was examined because pigmentation had appeared 5 months earlier. The cutaneous lesions were blue-grey, macular (diameter: 2-3 cm), with a predilection for the trunk, the lower part of the neck and the proximal part of the legs. There was no pruritus and the lesions did not urticate when rubbed. Histologically, there was epidermal acanthosis, moderate hyperkeratosis and dermal infiltration with numerous melanophages. The clinical lesions remained stable 6 months later.

CONCLUSION

The cutaneous manifestations and their course are similar to those of idiopathic macular pigmentation usually reported in adolescents. Ultramicroscopic findings have led some authors to classify it as lichen planus.