Expression of the clock gene Rev-erbα in the brain controls the circadian organisation of food intake and locomotor activity, but not daily variations of energy metabolism.

The nuclear receptor REV-ERBα is part of the molecular clock mechanism and is considered to be involved in a variety of biological processes within metabolically active peripheral tissues as well. To investigate whether Rev-erbα (also known as Nr1d1) in the brain plays a role in the daily variations of energy metabolism, feeding behaviour and the sleep-wake cycle, we studied mice with global (GKO) or brain (BKO) deletion of Rev-erbα. Mice were studied both in a light/dark cycle and in constant darkness, and then 24-hour variations of Respiratory quotient (RQ) and energy expenditure, as well as the temporal patterns of rest-activity and feeding behaviour, were recorded. The RQ increase of GKO mice was not detected in BKO animals, indicating a peripheral origin for this metabolic alteration. Arrhythmic patterns of locomotor activity were only found in BKO mice. By contrast, the circadian rhythm of food intake was lost both in GKO and BKO mice, mostly by increasing the number of daytime meals. These changes in the circadian pattern of feeding behaviour were, to some extent, correlated with a loss of rhythmicity of hypothalamic Hcrt (also named Orx) mRNA levels. Taken together, these findings highlight that Rev-erbα in the brain is involved in the temporal partitioning of feeding and sleep, whereas its effects on energy metabolism are mainly exerted through its peripheral expression.

Inhibition promotes long-term potentiation at cerebellar excitatory synapses.

The ability of the cerebellar cortex to learn from experience ensures the accuracy of movements and reflex adaptation, processes which require long-term plasticity at granule cell (GC) to Purkinje neuron (PN) excitatory synapses. PNs also receive GABAergic inhibitory inputs via GCs activation of interneurons; despite the involvement of inhibition in motor learning, its role in long-term plasticity is poorly characterized. Here we reveal a functional coupling between ionotropic GABAA receptors and low threshold CaV3 calcium channels in PNs that sustains calcium influx and promotes long-term potentiation (LTP) at GC to PN synapses. High frequency stimulation induces LTP at GC to PN synapses and CaV3-mediated calcium influx provided that inhibition is intact; LTP is mGluR1, intracellular calcium store and CaV3 dependent. LTP is impaired in CaV3.1 knockout mice but it is nevertheless recovered by strengthening inhibitory transmission onto PNs; promoting a stronger hyperpolarization via GABAA receptor activation leads to an enhanced availability of an alternative Purkinje-expressed CaV3 isoform compensating for the lack of CaV3.1 and restoring LTP. Accordingly, a stronger hyperpolarization also restores CaV3-mediated calcium influx in PNs from CaV3.1 knockout mice. We conclude that by favoring CaV3 channels availability inhibition promotes LTP at cerebellar excitatory synapses.

Specific IgE levels do not indicate persistence or transience of food allergy in children with atopic dermatitis.

BACKGROUND: Food allergy in early childhood usually resolves with time; however, little is known about predictors for persistence or transience of food allergy in children with atopic dermatitis. The aim of the study was to evaluate whether specific IgE levels in serum could be a useful predictor of the outcome of oral re-challenges. METHODS: In 74 children, 99 oral food challenges were performed (cow milk n = 48, hen egg n = 37, and wheat n = 14) and repeated after a median time interval of 16 months. In 15 of the 74 children, a third challenge (n = 22) could be performed, with a median time interval from second challenge to third challenge of 15 months. RESULTS: There were 37 children with transient food allergy (positive first challenge and negative second challenge), while 62 children had persistent food allergy (positive first challenge and negative second challenge). Comparison of the two groups showed that specific IgE as well as total IgE in serum was significantly higher in the latter group. However, looking at the time course, specific IgE did not decrease significantly during elimination diet. CONCLUSION: Our results indicate that specific IgE in serum--although very helpful at the time of the first diagnosis--cannot predict whether a chid will become tolerant after a period of avoidance. Therefore, oral re-challenges remain mandatory.

Anaphylactic reaction to lychee in a 12-year-old girl: cross-reactivity to latex?

There are very few case reports on allergic reactions to lychee in the literature - so far only in adults. We report on a 12-year-old girl who developed swelling of lips, pruritus, generalized urticaria and dyspnea 30 min after eating a raw lychee. A second event occurred after eating a piece of cake covered with a fruit cocktail. All other foods were well tolerated. In infancy the girl had suffered from atopic dermatitis, which disappeared in childhood; for the previous 2 yr she had presented with seasonal allergic rhinoconjunctivitis. Upon oral provocation, she developed restlessness, flush, generalized urticaria and inspiratory stridor 50 min after eating half a lychee. The diagnostic work up showed a clear positive skin prick test to raw lychee and specific immunoglobulin E (IgE) in serum to latex but not to lychee. In the cellular antigen stimulation test (CAST) carried out with lychee extracts in several concentrations, the same positive results could be found confirming an allergic reaction. Cross-reactivity of lychee to latex was shown by inhibition experiments using the UniCAP 100-system. In conclusion, it seems worthwhile considering the rare allergy to lychee in the case of unclear food-allergic reactions and lychee should be added to the list of foods cross-reacting with latex.

Predictors of positive food challenge outcome in non-IgE-mediated reactions to food in children with atopic dermatitis.

BACKGROUND: Atopic dermatitis is frequently associated with food allergy. In general, clinically manifested food allergy is regarded as IgE mediated. However, there are some children with food allergy for whom IgE hypersensitivity cannot be proven. OBJECTIVE: The aim was to evaluate the percentage of children with positive double-blind, placebo-controlled food challenge (DBPCFC) results but without any proof of IgE sensitization and to characterize this subgroup of children. METHODS: Two hundred eight DBPCFCs were performed in 139 children (median age, 13 months) with atopic dermatitis and suspected food-related clinical symptoms. All children were subjected to skin prick tests (SPTs), determination of specific IgE, and atopy patch tests. RESULTS: One hundred eleven (53%) of 208 oral food challenge results were assessed as positive. Positive challenge results were separated into 2 groups according to IgE positivity: negative SPT and negative specific IgE results in serum (group A, n = 12) and positive SPT, specific IgE, or both results in serum (group B, n = 99). The atopy patch test results; the distribution of early, late, or both clinical reactions; the age of the children; and the total IgE levels all showed no significant differences between the 2 groups. However, wheat challenge results were more often positive among the apparently non-IgE-sensitized children, and hen's egg challenge results were more often positive in the sensitized group (P < .05). CONCLUSION: Around 10% of positive DBPCFC results are not IgE mediated. Therefore not the proof of specific IgE but the suspicion of food-related symptoms should be the indication to perform oral food challenges, especially in the case of wheat. Otherwise, some children will not receive diagnoses for food allergy and be denied the benefits of a specific diet.

Neuropeptide Y and epilepsy: varying effects according to seizure type and receptor activation.

In vitro and in vivo experiments suggest antiepileptic properties for NPY. In this study, the pharmacology of these effects was examined and compared in different rat models of seizures. Agonists for Y(1), Y(2) and Y(5) receptors reduced seizure-like activity in hippocampal cultures. Intracerebral injection of NPY or Y(5) agonists reduced the expression of focal seizures produced by a single electrical stimulation of the hippocampus. Conversely, NPY agonists increased the duration of generalized convulsive seizures induced by pentylenetetrazol. These results suggest that NPY reduces seizures of hippocampal origin through activation of Y(5) receptors. They also point to probable modulatory effects of NPY in brain structures other than the hippocampus, involved in initiation, propagation or control of seizures.

Atopy patch tests, together with determination of specific IgE levels, reduce the need for oral food challenges in children with atopic dermatitis.

BACKGROUND: Atopic dermatitis is commonly associated with food allergy. In addition to skin prick tests (SPTs) and measurements of specific IgE levels, the atopy patch test (APT) has recently been introduced into the diagnostic procedure for food allergy. OBJECTIVE: Our aim was to evaluate whether a combination of allergologic tests could improve the prognostic value of the individual tests for positive food challenge results. We hypothesized that the combination of a positive APT result plus proof of specific IgE, a positive SPT result, or both would render double-blind, placebo-controlled, food challenges unnecessary. METHODS: One hundred seventy-three double-blind, placebo-controlled, food challenges were performed in 98 children (median age, 13 months) with atopic dermatitis. All children were subjected to SPTs, APTs, and determination of specific IgE. Sensitivity, specificity, and positive and negative predictive values were calculated. RESULTS: Ninety-five (55%) of 173 oral provocations were assessed as positive. For evaluating suspected cow's milk (CM) allergy, the APT was the best single predictive test (positive predictive value [PPV], 95%), and the combination of a positive APT result with evidence of specific IgE or an APT result together with a positive skin prick test response optimized the PPV to 100%. For hen's egg (HE) allergy, the APT was also the best single predictive test (PPV, 94%). The combination of 2 or more tests did not exceed the APT's predictive value. In both CM and HE challenges, the predictability of oral challenges depended on the level of specific IgE. For wheat allergy, the APT proved to be the most reliable test, and the PPV of 94% could not be improved by a combination with other allergologic tests. CONCLUSION: The combination of positive APT results and measurement of levels of specific IgE (CM, > or = 0.35 kU/L; HE, > or = 17.5 kU/L) makes double-blind, placebo-controlled, food challenges superfluous for suspected CM and HE allergy.

Brain-derived neurotrophic factor delays hippocampal kindling in the rat.

Epileptic seizures increase the expression of brain-derived neurotrophic factor in the hippocampus. Since this neurotrophin exerts modulatory effects on neuronal excitability in this structure, it may play an important role in hippocampal epileptogenesis. This question was addressed by studying the effects of chronic infusions of recombinant brain-derived neurotrophic factor and brain-derived neurotrophic factor antisense in the hippocampus during the first seven days of hippocampal kindling. Infusion with brain-derived neurotrophic factor (6-24 microg/day) significantly delayed the progression of standard hippocampal kindling and strongly suppressed seizures induced by rapid hippocampal kindling. These suppressive effects were dose dependent, long lasting, not secondary to neuronal toxicity and specific to this neurotrophin, as nerve growth factor accelerated hippocampal kindling progression. They also appeared to be specific to the hippocampus, as infusion of brain-derived neurotrophic factor (48 microg/day) in the amygdala only resulted in a slight and transient delay of amygdala kindling. Conversely to the protective effects of exogenous brain-derived neurotrophic factor, chronic hippocampal infusion of antisense oligodeoxynucleotides (12 nmol/day), resulting in reduced expression of endogenous brain-derived neurotrophic factor in the hippocampus, aggravated seizures during hippocampal kindling. Taken together, our results lead us to suggest that the seizure-induced increase in brain-derived neurotrophic factor expression in the hippocampus may constitute an endogenous regulatory mechanism able to restrain hippocampal epileptogenesis.

What safety measures need to be taken in oral food challenges in children?

BACKGROUND: Food allergens are often accused of causing numerous ailments. This is particularly true for the pediatric population, where the incidence of food allergy is four times as high as in adults. As food challenges may provoke life-threatening reactions, intensive safety measures need to be taken during provocation, and prompt medical intervention may become necessary. METHODS: We retrospectively evaluated 349 oral challenges in 204 children with atopic dermatitis, looking for criteria to help the physician decide which patients need medical intervention. RESULTS: A total of 178 (51%) oral food challenges with the four allergens (cow's milk [CM], hen's egg [HE], wheat, and soy) showed a positive clinical reaction. Of these, 120 (67%) needed medical intervention. In 42 (35%) cases, intervention was parenteral, and oral medication was given in 78 (65%) cases. There was a strong positive correlation (90%) between the level of specific IgE and the need for medical intervention (> or = 17.50 kU/l for CM, wheat, and soy; > or = 3.50 kU/l for HE). Patient history of food allergy was an indicator of the need for medical intervention (P = 0.01). A positive patient history and a high level of specific IgE were significantly (P=0.003) associated with parenteral medication in HE. CONCLUSIONS: Patient history of food allergy is a reliable indicator of the need for medical intervention in the cases of CM, wheat, and soy regardless of the level of specific IgE. With HE, a positive patient history plus a high level of specific IgE significantly indicates the need for parenteral medication. On the basis of our results, we recommend establishing intravenous access in children with a level of specific IgE of > or = 17.50 kU/l (CAP class 4) to CM and wheat, or with specific IgE of > or =3.50 kU/l (CAP class 3) to HE.

Endogenous control of hippocampal epileptogenesis: a molecular cascade involving brain-derived neurotrophic factor and neuropeptide Y.

PURPOSE: Seizures increase the expression of brain-derived neurotrophic factor (BDNF) in the hippocampus. Because this neurotrophin exerts modulatory effects on hippocampal neuronal excitability, it may play an important role in epileptogenesis initiated in this structure. Moreover BDNF is known to regulate the expression of neuropeptide Y (NPY), which displays modulatory properties on seizure activity. This suggests that the effects of BDNF on epileptogenesis may be mediated by NPY. METHODS: Adult male rats received a 7-day chronic intrahippocampal infusion of BDNF, BDNF antisense oligodeoxynucleotides, NPY, or anti-NPY immunoglobulin G during kindling of the hippocampus. The long-term regulation of NPY expression by BDNF was also studied by immunohistochemistry and radioimmunoassay. RESULTS: BDNF applied during the first week of hippocampal stimulation significantly delayed the progression of kindling, an effect that outlasted the end of the infusion by at least 7 days. Conversely, infusion of BDNF antisense oligodeoxynucleotides to reduce the expression of endogenous BDNF in the hippocampus aggravated the electroencephalographic expression of seizures. Chronic infusion of BDNF increased the expression of NPY in the hippocampus, with a time course similar to that of the protective effect of the neurotrophin on kindling. Finally, chronic infusion of NPY in the hippocampus delayed the progression of hippocampal kindling, whereas anti-NPY antibodies had an aggravating effect. CONCLUSIONS: Our results suggest that the seizure-induced increase in BDNF expression in the hippocampus may constitute an endogenous protective mechanism able to counteract hippocampal epileptogenesis. This protective effect appears to be mediated at least in part through the regulation of NPY expression.

Neuroprotective effects of chronic estradiol benzoate treatment on hippocampal cell loss induced by status epilepticus in the female rat.

Neuroprotective properties of estrogen are supported by extensive experimental evidence. In this study, the effects of estrogen were examined on the neurodegeneration secondary to status epilepticus induced by kainic acid in the rat. Chronic supplementation of ovariectomized rats with estradiol benzoate (20 microg/day) did not modify the expression of seizures monitored by electroencephalography, but significantly reduced cellular loss in the hippocampus. This neuroprotection was in particular observed in the dentate hilus and CA3 pyramidal layer when treatment with estradiol benzoate was started five days before status epilepticus induction. These findings suggest that estrogen can exert neuroprotective effects in a model of status epilepticus, in the absence of anti-epileptic properties.

Overexpression of neuropeptide Y induced by brain-derived neurotrophic factor in the rat hippocampus is long lasting.

Brain-derived neurotrophic factor (BDNF) plays an important role in hippocampal neuroplasticity. In particular, BDNF upregulation in the hippocampus by epileptic seizures suggests its involvement in the neuronal rearrangements accompanying epileptogenesis. We have shown previously that chronic infusion of BDNF in the hippocampus induces a long-term delay in hippocampal kindling progression. Although BDNF has been shown to enhance the excitability of this structure upon acute application, long-term transcriptional regulations leading to increased inhibition within the hippocampus may account for its suppressive effects on epileptogenesis. Therefore, the long-term consequences of a 7-day chronic intrahippocampal infusion of BDNF (12 microg/day) were investigated up to 2 weeks after the end of the infusion, on the expression of neurotransmitters contained in inhibitory hippocampal interneurons and which display anti-epileptic properties. Our results show that BDNF does not modify levels of immunostaining for glutamic acid decarboxylase, the rate-limiting enzyme for gamma-aminobutyric acid (GABA) synthesis, and somatostatin. Conversely, BDNF induces a long-lasting increase of neuropeptide Y (NPY) in the hippocampus, measured by immunohistochemistry and radioimmunoassay, outlasting the end of the infusion by at least 7 days. The distribution of BDNF-induced neuropeptide Y immunoreactivity is similar to the pattern observed in animals submitted to hippocampal kindling, with the exception of mossy fibres which only become immunoreactive following seizure activity. The enduring increase of neuropeptide Y expression induced by BDNF in the hippocampus suggests that this neurotrophin can trigger long-term genomic effects, which may contribute to the neuroplasticity of this structure, in particular during epileptogenesis.

Selective susceptibility to inhibitors of GABA synthesis and antagonists of GABA(A) receptor in rats with genetic absence epilepsy.

Thalamocortical spike-and-wave discharges characterize the nonconvulsive absence seizures that occur spontaneously in genetic absence epilepsy rats from Strasbourg (GAERS), a selected strain of Wistar rats. GABA is crucial in the generation of absence seizures. The susceptibility to convulsions induced by threshold doses of various GABA receptor antagonists and inhibitors of GABA synthesis, kainic acid and strychnine, was compared in GAERS and in nonepileptic rats from a selected control strain (NE). The brain structures involved in the drug-elicited convulsive seizures were mapped by c-Fos immunohistochemistry. Injection of various antagonists of the GABA(A) receptor, bicuculline and picrotoxin, and inverse agonists of the benzodiazepine site (FG 7142 and DMCM) induced myoclonic spike-and-wave discharges followed by clonic or tonic-clonic seizures with high paroxysmal activity on the cortical EEG. The incidence of the convulsions was dose-dependent and was higher in GAERS than in NE rats. Mapping of c-Fos expression showed that the frontoparietal cortex was constantly involved in the convulsive seizures elicited by a threshold convulsant dose, whereas limbic participation was variable. In contrast, GAERS were less susceptible than NE rats to the tonic-clonic convulsions induced by the inhibitors of glutamate decarboxylase, isoniazide and 3-mercaptopropionic acid. The GABA(B) receptor antagonist CGP 56999 and kainic acid induced a similar incidence of seizures in GAERS and NE rats and predominantly activated the hippocampus. No difference in the tonic seizures elicited by strychnine could be evidenced between the strains. These results suggest that an abnormal cortical GABAergic activity may underlie absence seizures in GAERS.

The atopy patch test (APT)-- a useful tool for the diagnosis of food allergy in children with atopic dermatitis.

BACKGROUND: While immediate-type clinical reactions to food can quite easily be identified by history or measurement of specific IgE in combination with positive oral food challenges, the evaluation of food allergy in the absence of immediate clinical reactions still presents diagnostic difficulties--particularly in children with atopic dermatitis. The objective of this study was to evaluate the diagnostic value of the atopy patch test (APT) with regard to late-phase reactions observed in double-blind, placebo-controlled food challenges with cow's milk, hen's egg, wheat, and soybean. METHODS: We investigated 75 children (median age 2.1 years) with suspected food allergy by double-blind, placebo-controlled food challenges, specific IgE in serum, skin prick test, and APT. Of the subjects, 69/75 suffered from atopic dermatitis. RESULTS: Of 209 oral challenges, 133 were performed with allergen and 76 with placebo. We assessed 77/133 allergen and 2/76 placebo challenges as positive. In 66 of 77 (86%) positive oral challenges, specific IgE in serum to the corresponding allergen was positive; in 64/77 (83%) the skin prick test, and in 42/77 (55%) the APT was positive. While immediate-type reactions were associated with positive skin prick test and proof of specific IgE in serum, late-phase clinical reactions were associated with a positive APT (sensitivity 76%, specificity 95%). CONCLUSIONS: The APT seems to be a valuable additional tool in the diagnostic work-up of food allergy in children with atopic dermatitis - especially with regard to late-phase clinical reactions. The APT may help to prevent unnecessary restrictive diets which may be the consequence of misjudging late reactions by clinical assessment alone.

[Treatment of soft tissue sarcomas of the extremities and the trunk by conservative surgery and postoperative irradiation. Apropos of a series of 96 patients]. / Traitement des sarcomes des parties molles des extrémités et du tronc par chirurgie conservatrice et irradiation postopératoire. A propos d'une série de 96 patients.

AIM OF STUDY: Retrospective study of a series of 96 patients presenting with soft tissues sarcoma. Homogeneous treatment between 1980-1992 with conservative surgery and post operative irradiation. PATIENTS AND METHODS: Median age of the 96 patients was 58 years. Tumor site was: upper limb 20, lower limb 46, trunk 30. In 35 cases largest diameter of the tumor was 5 cm or less (T1). All patients were M0. The most frequent pathological sub type was: malignant histiocytofibroma 28, liposarcoma 28. A gross complete surgery was performed in 89 cases. Radiotherapy was performed with cobalt or x 18 MV photons. The dose delivered was 50 Gy with a boost of 10 Gy. No adjuvant chemotherapy was given. RESULTS: Mean follow up was 68 months. Local relapse was seen in 19 patients, six were salvaged by surgery, a limb amputation rates were necessary in 4 cases. The 5 and 10 year-overall survival was 70% and 64%. There was no severe radiation toxicity requiring surgery. A good function of the limb was preserved in all cases. CONCLUSION: These results are in agreement with those of the literature and justify a conservative approach for these soft tissues sarcomas.

Safety and characterization of the immune response engendered by two combined measles, mumps and rubella vaccines.

We performed a randomized trial to compare the safety and immunogenicity of two combined measles, mumps and rubella vaccines in healthy children 14-24 months of age. Triviraten Berna Vaccine (Swiss Serum and Vaccine Institute), contains the Edmonston Zagreb 19 strain of measles virus, the Rubini mumps virus strain and the Wistar RA 27/3 rubella strain while MMR-Vax (Merck, Sharp & Dohme, West Point, PA) contains the Enders attenuated Edmonston measles strain, the Jeryl Lynn mumps strain and the Wistar RA 27/3 rubella strain. Immunization with Triviraten Berna was associated with a significantly lower incidence of swelling and redness at the injection site in addition to a reduced rate of fever compared with MMR-Vax. Seroconversion rates for the measles and rubella vaccine components were comparable in all tests used. However, seroconversion for the mumps vaccine component was test-dependent. Using an ELISA, the seroconversion rate following immunization with MMR-Vax was significantly (P < 0.01) higher than for Triviraten Berna. In contrast, nearly identical rates were obtained using an indirect immunofluorescence test. Both vaccines were equally effective at engendering antibodies capable of neutralizing wild type mumps virus. Geometric mean ELISA antibody titers against measles and mumps virus were higher following immunization with MMR-Vax while that for rubella was higher after immunization with Triviraten Berna. A small number (N = 13) of adolescents immunized either with MMR-Vax or Triviraten Berna were reimmunized with Triviraten Berna and various humoral and cellular response parameters to the measles and mumps vaccine components analyzed. While few subjects mounted a humoral antibody response to measles, most likely due to elevated baseline titers, there was a marked lymphoproliferative response. Anti-mumps virus ELISA antibody titers were higher both at baseline and after reimmunization in subjects who received MMR-Vax for primary immunization. However, there was no difference in either neutralizing titer or proliferative response in subjects primed with MMR-Vax or Triviraten Berna either before or after reimmunization.

Protective effects of brain-derived neurotrophic factor on the development of hippocampal kindling in the rat.

Recent data have suggested the involvement of neurotrophins in the cascade of events occurring during seizure development. In particular, expression of both brain-derived neurotrophic factor (BDNF) and its receptor mRNAs increases in different brain structures after convulsive seizures. The physiological significance of this increase was investigated by chronic intrahippocampal perfusion of BDNF in the model of dorsal hippocampal kindling in the rat. A 7 day perfusion of BDNF, in the region of the stimulating electrode, blocked the development of kindling during the perfusion period and for the following 15 days. These results provide in vivo evidence for a protective role of BDNF in the regulation of plasticity involved in epileptogenesis in adult brain.