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J Egger

Publications and source records attributed to J Egger.

At least 19 recordsLinked to original sources
PubMed2003

High statistics measurement of the K+-->pi0e+nu (K+e3) branching ratio.

E865 at the Brookhaven National Laboratory AGS collected about 70 000 K(+)(e3) events to measure the K(+)(e3) branching ratio relative to the observed K+-->pi(+)pi(0), K+-->pi(0)micro(+)nu, and K+-->pi(+)pi(0)pi(0) decays. The pi(0) in all the decays was detected using the e(+)e(-) pair from pi(0)-->e(+)e(-)gamma decay and no photons were required. Using the 2002 Particle Data Group branching ratios for the normalization decays, we obtain BR(K(+)(e3(gamma)))=(5.13+/-0.02(stat)+/-0.09(syst)+/-0.04(norm))%, where K(+)(e3(gamma)) includes the effect of virtual and real photons. This result is approximately 2.3sigma higher than the current Particle Data Group value. Implications for the V(us) element of the CKM matrix, and the matrix's unitarity are discussed.

Journal Article↗
PubMed2002

Experimental study of the radiative decays K+-->mu(+)nue(+)e(-) and K+-->e(+)nue(+)e(-).

Experiment 865 at the Brookhaven Alternating Gradient Synchrotron obtained 410 K+-->e(+)nue(+)e(-) and 2679 K+-->mu(+)nue(+)e(-) events including 10% and 19% background. The branching ratios were measured to be [2.48+/-0.14(stat)+/-0.14(syst)]x10(-8) (m(ee)>150 MeV) and (7.06+/-0.16+/-0.26)x10(-8) (m(ee)>145 MeV), respectively. Results for the decay form factors are presented.

Journal Article↗
PubMed2001

New measurement of K(+)(e4) decay and the s-pave pi pi-scattering length a(0)(0).

A sample of 4 x 10(5) events from the decay K(+)-->pi(+)pi(-)e(+)nu(e) (K(e4)) has been collected in experiment E865 at the Brookhaven Alternating Gradient Synchrotron. The analysis of these data yields new measurements of the K(e4) branching ratio [(4.11+/-0.01+/-0.11) x 10(-5)], the s-wave pi pi scattering length [a(0)(0) = 0.216+/-0.013(stat)+/-0.004(syst)+/-0.005(theor)], and the form factors F, G, and H of the hadronic current and their dependence on the invariant pi pi mass.

Journal Article↗
PubMed2000

Search for lepton flavor violation in K+ decays into a charged pion and two leptons.

A search for lepton flavor violating decays, K+ --> mu+ mu+ pi-, K+ --> e+ e+ pi-, K+ --> pi+ e+ mu-, K+ --> mu+ e+ pi-, and pi0 --> e+ mu-, was performed using the data collected in Experiment E865 at the Brookhaven Alternating Gradient Synchrotron. No signal was found in any of the decay modes. At the 90% confidence level, the branching ratios are less than 3.0x10(-9), 6.4x10(-10), 5. 2x10(-10), 5.0x10(-10), and 3.4x10(-9), respectively.

Journal Article↗
PubMed2000

Improved limit on the rate of the decay K+ --> pi(+)&mgr;(+)e(-)

We report results of a search for the lepton-family number violating decay K+-->pi(+)&mgr;(+)e(-) from data collected by experiment E865 in 1996 at the Alternating Gradient Synchroton of Brookhaven National Laboratory. We place an upper limit on the branching ratio at 3.9x10(-11) ( 90% C.L.). Together with results based on data collected in 1995 and an earlier experiment, E777, this result establishes a combined 90% confidence level upper limit on the branching ratio at 2.8x10(-11). We also report a new upper limit on the branching ratio for pi(0)-->&mgr;(+)e(-) of 3.8x10(-10) ( 90% C. L.).

Journal Article↗
PubMed2000

New measurement of the rare decay K+ --> pi(+)&mgr;(+)&mgr;(-)

More than 400 K+-->pi(+)&mgr;(+)&mgr;(-) events were observed in a rare K+ decay experiment at the Brookhaven Alternating Gradient Synchrotron. Normalized to the K+-->pi(+)pi(+)pi(-) decay, the branching ratio is determined to be [9.22+/-0.60(stat)+/-0. 49(syst)]x10(-8). This branching ratio and the &mgr;&mgr; mass spectrum is in very good agreement with the measurement of the K+-->pi(+)e(+)e(-) decay, but deviates significantly from the previous measurement.

Journal Article↗
PubMed1999

Normative volumetric data of the developing hippocampus in children based on magnetic resonance imaging.

PURPOSE: To acquire normative data of the hippocampus and its postnatal growth in 50 children (age, 1 month to 15 years) without epilepsy. METHODS: Morphometry of the hippocampus was carried out by using a spoiled FLASH 3D sequence (sagittal orientation), whereas the volume of the brain was assessed with a T2-weighted spin-echo sequence (transverse orientation). The volume of the hippocampus and the brain was determined by following Cavalieri's principle. Growth curves of the brain and hippocampus were fitted to a nonlinear Boltzmann sigmoidal equation. RESULTS: Intra-/interobserver coefficient of variation was 2.0/4.9% for hippocampal volume measurements and 2.0/2.1% for brain volumetry. A significant difference in volume was noted between the right and left hippocampus (p < 0.001), with the right side being larger on average by 0.10 cc. Correlation coefficients of growth curves ranged between 0.71 and 0.94. Growth curves demonstrated a faster development of the hippocampus in girls. A steeper slope of hippocampal growth as compared with brain growth was found in girls, whereas in boys, the slope of brain growth was steeper. CONCLUSIONS: Our findings will be of help in evaluating vulnerable phases of the hippocampal formation with accelerated growth, thereby leading to a better understanding of the development of hippocampal sclerosis in early childhood.

Adolescent↗
PubMed1999

[Psychic coping with spontaneous abortion].

Spontaneous abortion is the early and involuntary loss of pregnancy and occurs in about 15 to 20% of all pregnancies. In this study, Filipp's heuristic model for critical life events was used to evaluate general and specific causal attributions and depressive symptoms after spontaneous abortion. A sample of 100 women was investigated at four measuring points between diagnosis and five weeks after the spontaneous abortion. The results regarding depressive symptom levels showed that two days after the miscarriage, 50% of the women were severely depressed, and five weeks later 30% were still depressed. Depressive symptoms were increased in cases of prior reproductive loss and when pregnancy was planned or desired. With regard to general causal attributions, women who tended to more internal, stable, and global attributions showed a significantly higher level of depressive symptoms than women with external, unstable, and specific attributions. In the area of specific attributions regarding pregnancy loss, the same patterns of results were found.

Abortion, Spontaneous↗
PubMed1997

MRI of primary meningeal sarcomas in two children: differential diagnostic considerations.

Meningeal sarcomas are very rare, highly aggressive tumours affecting children more frequently than adults. The clinical course and MRI of meningeal sarcomas in two cases are discussed with special regard to possible misinterpretation. In one case MRI demonstrated a circumscribed mass in contact with the meninges, with central areas of haemorrhage. In the other, a case of primary leptomeningeal sarcomatosis, several MRI examinations over the course of almost a year were unhelpful, despite severe neurological complaints. Then MRI revealed meningeal contrast enhancement all over the brain and spinal canal, together with cerebral infarcts. MRI of meningeal sarcomas has not been discussed in the literature. MRI did not permit specific diagnosis, but enabled visualisation of the extent of the tumour and/or meningeal involvement. Early histological diagnosis is indispensable for adequate treatment.

Child↗
PubMed1997

Topographic mapping of brain electrical activity in children with food-induced attention deficit hyperkinetic disorder.

UNLABELLED: In 15 children suffering from food induced attention deficit hyperkinetic syndrome, topographic EEG mapping of brain electrical activity was carried out following avoidance and ingestion of previously identified provoking foods. A crossover design was used and recordings were interpreted independently by two investigators, one of whom was blind to the order of testing. During consumption of provoking foods there was a significant increase in betal activity in the frontotemporal areas of the brain. This investigation is the first one to show an association between brain electrical activity and intake of provoking foods in children with food-induced attention deficit hyperactivity disorder. CONCLUSIONS: These data support the hypothesis that in a subgroup of children with attention deficit hyperactivity disorder certain foods may not only influence clinical symptoms but may also alter brain electrical activity.

Adolescent↗
PubMed1996

Endocrine disorders in septo-optic dysplasia (De Morsier syndrome)--evaluation and follow up of 18 patients.

UNLABELLED: Septo-optic dysplasia (SOD) is characterized by hypoplasia of the optic nerve, various types of forebrain defects and hormonal deficiencies. We have studied the clinical and endocrinological characteristics of 18 such patients retrospectively to: (1) better define the endocrine abnormalities in children with SOD; and (2) to find approaches for the interdisciplinary long-term care of children with SOD. The children were seen at the Children's Hospital of the University of Munich from 1976 to 1992 (8 boys, 10 girls; age at initial presentation: 1 day-13 years of age, mean 1.9 years). Unilateral hypoplasia of the optic nerve was found in 7 cases, bilateral hypoplasia in 11. Sonographic, CCT or MRI yielded the following results: 4 of the patients had a cavum septum pellucidum, 3 patients had hypoplasia of the cerebellum, 1 aplasia of the corpus callosum and 1 aplasia of the fornix. An empty sella with or without an ectopic pituitary was seen in 4 cases. Height standard deviation score (SDS) at time of diagnosis was -4.0 to +0.4, mean -2.92. Endocrine deficiencies were present in all 11 patients who had undergone endocrinological investigations. Seven patients suffered from isolated growth hormone (GH) deficiency or multiple hypopituitarism. One had diabetes insipidus centralis, 2 had hypogonadotropic hypogonadism, 1 had hypothyroidism and 2 adrenal insufficiency. Hypothalamic testing was performed only in a subset of patients: in 5 of 11 children tested a thyrotropin releasing hormone (TRH test), in two out of nine a gonadotropin releasing hormone (GnRH) test, and in three out of six GH releasing hormone (GHRH) test yielded abnormal results. High prolactin levels were measured in two out of five patients. CONCLUSION: SOD is characterized by optic nerve hypoplasia and a variety of endocrine deficiencies. In addition, forebrain malformations are present in most SOD patients. Hormonal disorders are present in some SOD patients which may be of hypothalamic origin and need to be investigated systematically.

Adolescent↗
PubMed1994

Glutamate in pyridoxine-dependent epilepsy: neurotoxic glutamate concentration in the cerebrospinal fluid and its normalization by pyridoxine.

BACKGROUND: Pyridoxine-dependent epilepsy is a rare autosomal recessive disorder. Untreated patients suffer from a progressive encephalopathy with mental retardation, intractable epilepsy, and progressive neurological signs and symptoms. Lifelong supplementation with vitamin B6 is the treatment of choice. However, despite early treatment, many patients develop mental retardation. OBJECTIVES: To assess the role of glutamate as an excitatory neurotransmitter and neurotoxin in pyridoxine-dependent epilepsy. METHODS: We examined cerebrospinal fluid (CSF) levels of glutamate, gamma-aminobutyric acid, and pyridoxal-5'-phosphate in a patient with pyridoxine dependency while on and off vitamin B6 treatment. RESULTS: Off vitamin B6 the glutamate level was two hundred times normal. An intermediate dose of vitamin B6 (5 mg/kg BW/day) caused normalization of the EEG and remission of the seizures, but the CSF glutamate concentration was still ten times normal. With a higher dose of pyridoxine (10 mg/kg BW/day) the CSF glutamic acid normalized. CONCLUSIONS: The results indicate that control of epilepsy might not suffice as the therapeutic aim in treating of pyridoxine dependency. In view of the evidence for the role of excitatory amino acids in destruction of CNS nerve cells, the optimal treatment must counteract the raised levels of CSF glutamate and the dosage of vitamin B6 must be adjusted accordingly. The development of mental retardation might theoretically be prevented by adjusting the dose of vitamin B6 to achieve not only remission of epilepsy but also normalization of CSF glutamate.

Adrenocorticotropic Hormone↗